Patent Publication Number: US-2012029367-A1

Title: Heart rate waterproof measuring apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the following foreign application, which is incorporated herein by reference in its entirety: Lebanese Serial Patent No. 9099, filed Jul. 31, 2010. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     n/a 
     FIELD OF THE INVENTION 
     The present invention relates to a waterproof heart rate measuring apparatus that can be mounted on or integrated with eyewear such as swimming goggles. 
     BACKGROUND OF THE INVENTION 
     Heart rate monitoring is one of the most important tools for efficient cardiovascular training. As an indicator of not only the level of physical exertion but also the body&#39;s physiological adaptation to exercise, heart rate is a basis on which to gauge overall fitness. Additionally, monitoring heart rate is an easy way to make sure the body is not being dangerously overexerted. Many types of heart rate monitoring devices are known in the art, including devices that are worn around the wrist, on a finger, or around the torso, and those that use pressure, light, electrodes, and other methods to measure heart rate. 
     Heart rate is defined as the number of heart beats per unit of time, usually expressed as beats per minute (bpm), and can change as the body&#39;s need for oxygen changes in response to activity. The maximum heart rate, defined as the maximum safe heart rate for an individual, depends on factors such as age, sex, and fitness level of the individual. The most accurate way of measuring the maximum heart rate is through a cardiac stress test, in which the individual exercises while being monitored by an electrocardiograph (EKG). For general purposes, however, a formula is used to estimate Maximum Heart Rate: 
       HR max =220−age.
 
     There is a direct relationship between heart rate and intensity of physical activity. Three different training zones are commonly used: weight loss, fitness, and maximum performance. If an individual wishes to lose weight, the individual should limit heart rate to 50% to 70% of the individual&#39;s maximum heart rate during exercise. To increase fitness, an individual should limit heart rate to 70% to 85% of maximum heart rate. An individual who wants to improve athletic performance should aim for a heart rate that is higher than 85% of the individual&#39;s maximum heart rate. In professional athletic training, an athlete may utilize all three heart rate zones for building cardiovascular health and endurance. 
     A number of heart rate sensors are known, including those that use sound, light, and/or pressure to measure the pulse. One type of sensor is an infrared plethysmograph. Such a sensor includes a photodiode that emits an infrared light and a phototransistor that receives the reflected infrared light. The superficial temporal artery, a major artery of the head that is located approximately 5 mm below the skin of the temple, is commonly used for heart rate measurement. It is the smaller of the two branches of the external carotid artery, and its pulse is palpable superior to the zygomatic arch and anterior to and superior to the tragus. The pulse is calculated from the changes in volume of the temporal artery between the systole and diastole phases. In the diastole phase, the cavities of the heart are expanded and fill with blood, resulting in low arterial blood pressure. The heart contracts in the systole phase, resulting in higher blood pressure. The amount of blood in an artery is directly related to its volume: more blood (higher volume) in the systole phase and less blood (lower volume) in the diastole phase. There is a slight increase in the infrared light absorption by the artery during the systolic phase, and less light is reflected back to the phototransistor of the sensor. 
     Athletes and participants in every sport can benefit from monitoring heart rate during training, including swimmers. Taking accurate and frequent heart rate measurements not only is useful in tracking changes in cardiovascular fitness over time and optimizing training, but also to prevent injury and exercise stress. If not correctly monitored, a swimmer can easily overtrain, which means that heart rate is so high that the swimmer is training in an anaerobic zone. Although anaerobic training can be a part of a balanced training program, an anaerobic workout can damage the muscle cell walls and result in decreased aerobic capacity for 24 to 96 hours. Consistently training in the anaerobic zone is counterproductive and can lead to injury and fatigue. The traditional method of measuring heart rate is to count the number of pulses over one minute. Heart rate measurements are of the greatest training value when measured during the physical activity, but it is difficult to accurately measure swimming heart rate using the wrist or neck pulse because of human error and the inconvenience of having to stop swimming long enough to measure heart rate. A heart rate monitoring device is preferable, but the device options are limited by the additional need for waterproofing and a practical means of communicating heart rate and other biofeedback data. 
     An effective heart rate monitor for swimmers must also be able to communicate current heart rate to the user in a way that does not disrupt training. Devices worn on the wrist, for example, are inconvenient because the user cannot see the display while swimming. Other devices may be able to display a number in the user&#39;s field of view, but the user must still concentrate enough to read the numbers. This may not be an easy task while the user is swimming quickly or is focused on stroke technique. 
     Also, some swimmers use certain training devices that do not interrupt swimming, such as pacing devices, timers, and lap counters. However, no device offers a combination of a heart rate monitor, pacing device, timer, lap counter, and other features such as pulse oximetry and calorie monitoring. Furthermore, no device displays heart rate to the user in a non-numeric method that the user can interpret easily while swimming. 
     It would therefore be advantageous to provide a waterproof heart rate monitoring device that is convenient to use during swimming and also is capable of measuring and recording other types of biofeedback and non-biofeedback data. For example, the microcontroller  34  of the device may additionally comprise circuitry for performing the functions of a chronometer, timer, lap counter, distance measurement device, calorie counter, blood oximeter, and wireless transmitter (such as a Bluetooth® device). It would also be desirable that the device should include a method of wireless transmission so the measured biofeedback and non-biofeedback data could be sent from the device to a mobile phone or computer, or include an integrated memory chip that stores the data. Further, such a device should communicate heart rate to the user without requiring the user to divert attention away from training. 
     SUMMARY OF THE INVENTION 
     The present invention advantageously provides a biofeedback device, and the reflected infrared sensor used thereby, that can be mounted on or integrated with eyewear such as swimming goggles. The biofeedback device may comprise a heart rate measuring apparatus may measure the user&#39;s heart rate using a reflected-infrared plethysmograph (reflected infrared sensor) that detects heart rate from the temporal artery in the head. The reflected infrared sensor may transmit the detected heart rate signal to one or more amplifiers, one or more filters, and a microcontroller, which calculates the final heart rate measurement. 
     The heart rate measuring apparatus may also include a user interface by which the user can enter age, weight, target heart rate value or zone, and other data, or the heart rate measuring apparatus may be connected to a wireless interface (such as WiFi, infrared, or Bluetooth®) to incorporate a wireless user interface housed in a remote device. After the heart rate is measured, the measurement may be processed by a comparator that compares the user input values and the heart rate measurement. The heart rate measuring apparatus also may include circuitry that allows it to measure and record other biofeedback and non-biofeedback data such as calories burned and blood oxygen, and also data such as time, swim pace, swim duration, distance traveled, and laps completed. 
     The result of this comparison is communicated to the user by one or more signal elements, such as a display of colored light-emitting diodes (LEDs) on the inside of the goggles, the one or more signal elements notifying the user whether he should accelerate, decelerate, or maintain the current pace. The signal notification scheme may consist of LEDs of three or more colors, such as one color for each training zone (for example, weight loss, fitness, and maximum performance), with a blinking red color displayed when no heart rate is detected. Additionally, the lights may glow steadily or may blink at a variable rate depending on whether the user should speed up, slow down, or maintain the current pace to keep the user&#39;s heart rate within the desired training zone. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  shows a perspective view of a first embodiment of the heart rate waterproof measuring device; 
         FIG. 2A  shows a perspective view of a waterproof housing with the reflected infrared sensor contained therein; 
         FIG. 2B  shows a sectional view of the reflected infrared sensor within the housing, the reflected infrared sensor being covered by a thin waterproof layer of material; 
         FIG. 3  shows a second embodiment of the heart rate waterproof measuring device; 
         FIG. 4  shows an alternate sectional view of the device of  FIG. 3 ; 
         FIG. 5  shows a cross-sectional view of the reflected infrared sensor of the device and placement of the reflected infrared sensor on the skin above the temporal artery of the head; 
         FIG. 6A  shows a cross-sectional view of the waterproof housing including an reflected infrared sensor and panel-type sensor adjustment mechanism; 
         FIG. 6B  shows a sectional elevation view of the waterproof housing including the reflected infrared sensor and panel-type sensor adjustment mechanism; 
         FIG. 6C  shows the spiral-type sensor adjustment mechanism; 
         FIG. 7A  shows a sectional view of the device having rope-type LEDs located on the circumference of the inner surface of a lens; 
         FIG. 7B  shows a sectional view of the device having discrete LEDs located on the inner surface of a lens; 
         FIG. 8A  shows a sectional view of the device having a signal element coupled to a eye cup track positionable element; 
         FIG. 8B  shows a sectional view of the device having a signal element coupled to a suction cup positionable element; and 
         FIG. 9  shows a schematic diagram of an exemplary function of the device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Monitoring heart rate is very important in an athletic training program, especially swimming. Although there are many available types of heart rate monitors, not all are waterproof and convenient for use while swimming. Furthermore, none of the available waterproof heart rate monitors combine a heart rate measuring apparatus with the measurement of time, calories burned, swim pace, swim duration, blood oxygen, distance traveled, and laps completed. The present invention advantageously provides a biofeedback device that can be waterproofed and mounted on or integrated with eyewear such as swimming goggles. Heart rate is then communicated to the user by one or more signal elements positioned within the user&#39;s field of vision (if visual), or otherwise communicated to the user (if auditory or tactile). The present invention also advantageously provides a reflected infrared sensor used within the device, the reflected infrared sensor having optimal geometry for detecting heart rate from subcutaneous blood vessels, such as the superficial temporal artery. 
     Referring now to  FIG. 1 , a first embodiment of the biofeedback device  10  is shown. The biofeedback device  10  may comprise a pair of goggles  12 , a first waterproof housing  14 , a second waterproof housing  16 , and one or more wires  18  for electrical communication between the first and second waterproof housing  14 ,  16 . The goggles  12  may be a pair of traditional swimming goggles, or they may be any other type of protective eyewear. The goggles  12  may comprise a first and second eye cup  20   a ,  20   b , a first and second lens  22   a ,  22   b , a first and second eye cup gasket  24   a ,  24   b , and a head strap  26 . The first and second eye cups  20   a ,  20   b  may be composed of any transparent or semi-transparent material, including polycarbonate, optical-grade plastic, or even glass. The first and second eye cup gaskets  24   a ,  24   b  may be composed of any material suitable for contact with the face, although silicone and foam are the most popular materials. However, the goggles  12  may not include the first and second eye cup gaskets  24   a ,  24   b , as seen in Swedish goggles commonly used for competitive swimming. One or more signal elements  28 , such as LEDs  29 , either rope-type ( 29   a ) or discrete LEDs ( 29   b ), may be included within the interior of the eye cup. The one or more signal elements  28  may comprise any type of visual, auditory, or tactile signaling system that can communicate heart rate, pace, or other measurements to the user, and may communicate such in a non-alphanumeric manner. 
     The one or more signal elements  28  shown in the figures is an LED system, and the LEDs  29  are discussed in more detail below. The head strap  26  may also be of any suitable material, although the most popular materials are silicone and rubber (which are resilient) and the typical bungee cord (a cord with a core composed of a plurality of elastic strands, covered in a woven polypropylene or cotton sheath). The head strap  26  may comprise a single strap, a split single strap, a double strap, or any variation that will securely hold the goggles  12  to the user&#39;s head. 
     Continuing to refer to  FIG. 1 , the first waterproof housing  14  may contain therein the heart rate measuring apparatus  30  comprising a reflected infrared sensor  32 , a microcontroller  34 , and a user interface  36 . Although the term “heart rate measuring apparatus  30 ” is used herein for simplicity, it should be understood that the heart rate measuring apparatus  30  also may include circuitry that allows it to measure and record, in addition to heart rate, other biofeedback and non-biofeedback data such as calories burned and blood oxygen, and also data such as time, swim pace, swim duration, distance traveled, and laps completed. The user interface  36  may comprise one or more buttons  37  and one or more display screens  38 , or it may additionally or alternatively comprise any other operable elements such as knobs, switches, touch screens, etc. The microcontroller  34  of the heart rate measuring apparatus  30  calculates the heart rate. The reflected infrared sensor  32  transmits signals of voltage per unit of time to the microcontroller  34 , which may comprise one or more filters that filter all noise coming from electromagnetic interference and from ambient or environmental light and one or more amplifiers that amplify the remaining signal. The microcontroller  34  may then digitally filter the signal to extract the alternating current (AC) component of the signal, and then evaluate the time (T) between two pulses. The microcontroller  34  follows a formula to calculate the heart rate: 
       Heart Rate=60 /T    
     To obtain an accurate measurement over time, every five heart rate measurements may be averaged by the microcontroller  34  to obtain a moving average heart rate. A comparator may compare between the heart rate measurement and the target heart rate (calculated by the microcontroller  34  based on data entered in the user interface  36 ). Further, the microcontroller  34  may include a wireless communication interface adapted to be in wireless communication with a wireless data network, enabling transmission of recorded data to a computer, mobile phone, or other wireless device, or an integrated memory chip. The user interface  36  may also be in wireless communication with a wireless remote keyboard and display device, such as a dedicated device, mobile phone, PDA, or any other suitable device that is operable on wireless networks such as Bluetooth® or Wi-Fi. Additionally, the user interface  36  may be disposed within the first waterproof housing  14 , or it may be housed in a remote device  72  in wireless communication with the microcontroller  34  (shown in  FIG. 3 ). For simplicity, the term “microcontroller” as used herein may include the one or more filters, one or more amplifiers, comparator, wireless interface, and any other circuitry used to receive signals from the reflected infrared sensor  32  and perform calculations to produce final measurements and communicate said measurements to the user through a display element  28 . 
     Continuing to refer to  FIG. 1 , the second waterproof housing  16  may contain therein a power source  39  that may be rechargeable or single use, for example a small battery such as a hearing aid or watch battery (button cell). The first and second waterproof housings  14 ,  16  may be composed of any rigid or semi-rigid, lightweight, waterproof material, such as acrylic, to prevent water and humidity from entering the housing and coming in contact with the electronic elements, to protect the unit against shock damage (such as when the biofeedback device is dropped), and to increase stability to ensure accurate heart rate measurements. The housing shape may be oval or rounded to increase hydrodynamic efficiency, and the first and second waterproof housings  14 ,  16  each may include a mechanism (such as with a latch or screws) by which the user may open the waterproof housing to change the power source  39 , adjust the reflected infrared sensor  32 , or make repairs. All measurements taken by the reflected infrared sensor  32  rely on the accurate emission, reflection, and reabsorption of infrared light. Therefore, it is important to exclude as much ambient or environmental light as possible. To achieve this, the housing may further be coated with a layer of opaque material to block any interference by ambient or environmental light. 
     One or more wires  18  may put the first and second waterproof housings  14 ,  16  in electrical communication with each other and with the one or more signal elements  28  (if wireless communication is not used). These wires  18  may be disposed within a chamber defined by the frame of the goggles  12  that extends between the first and second waterproof housings  14 ,  16  and the one or more signal elements  28 . The wires  18  and may be rigid enough to be easily fed through the chamber so the waterproof housings  14 ,  16  and one or more signal elements  28  may be completely removed from the goggles  12 . Furthermore, the wires  18  may be coupled to a connection means on both ends so the wires  18  can be readily connected and disconnected from the waterproof housings  14 ,  16  and one or more signal elements  28 . 
     Continuing to refer to  FIG. 1 , the first and second waterproof housings  14 ,  16  may be held securely against the skin of the user by the head strap  26 , and the user may position the first and second housings for comfort and accuracy. The first waterproof housing  14  may have a first end  40   a  including a first strap attachment means  42   a  and a second end  40   b  including a second strap attachment means  42   b , and the second waterproof housing  16  may have a first end  44   a  including a first strap attachment means  46   a  and a second end  44   b  including a second strap attachment means  46   b , each strap attachment means  46   a ,  46   b  defining an opening through which the head strap  26  of the goggles  12  may pass. The first and second waterproof housings  14 ,  16  also may have a first surface  48   a ,  50   a  and second surface  48   b ,  50   b , the first surface  48   a ,  50   a  being in contact with the user&#39;s head and the second surface  48   b ,  50   b  being in contact with the head strap  26 . The second surface  48   b  of the first waterproof housing  14  may include the user interface  36 . 
     Continuing to refer to  FIG. 1 , it is understood that the heart rate measuring apparatus  30  (user interface  36 , microcontroller  34 , and reflected infrared sensor  32 ), power source  39 , wires  18 , and any other necessary components may be housed within a single waterproof housing. The power source  39  is shown in the first waterproof housing  14  in  FIG. 1  because it may optionally be included in the first waterproof housing  14 , with the second waterproof housing  16  being removed from the biofeedback device  10 . All other elements of the biofeedback device  10  are as described for the biofeedback device  10  shown in  FIG. 1 . 
     Now referring to  FIGS. 2A and 2B , the first surface  48   a  of the first waterproof housing  14  is shown. One or more screws  52  may be used to seal the housing  14 . As is also shown in  FIG. 1 , the first waterproof housing  14  may have a first end  40   a  and second end  40   b , the first end  40   a  including a first strap attachment means  42   a  and the second end  40   b  including a second strap attachment means  42   b . The first and second strap attachment means  42   a ,  42   b  each define an opening that may be wide enough to accommodate a typical head strap  26  (for example, the width may be approximately 0.2 cm to 1.0 cm), and may be tall enough to accommodate a typical head strap (for example, the height may be 0.5 cm to 2.0 cm). Each strap attachment means  42   a ,  42   b  opening may have an entry  54   a ,  56   a  on or adjacent the first surface  48   a  of the first waterproof housing  14  and an exit  54   b ,  56   b  on or adjacent the second surface  48   b  of the first waterproof housing  14  through which the head strap  26  may pass. For example, to attach the first waterproof housing  14  to the goggles  12  and ensure contact with the user&#39;s skin, the head strap  26  may be fed into the entry  54   a  of the first strap attachment means  42   a , then out the exit  54   b  of the first strap attachment means  42   a . The head strap  26  may then be in contact with the second surface  48   b  of the first waterproof housing  14 , passing from the first end  40   a  to the second end  40   b . Finally, the head strap  26  may be fed into the entry  56   a  and out the exit  56   b  of the second strap attachment mechanism  42   b . The first and second waterproof housings  14 ,  16  may each be positioned at any location on the strap  26  relative to the user, such as in the back of the user&#39;s head or on either side of and immediately adjacent to the eye cups  20   a ,  20   b . Although not shown in  FIG. 2A  or  2 B, it is understood that the second waterproof housing  16 , also having a first and second strap attachment means  46   a ,  46   b , may be attached to the goggles  12  in a similar manner. 
     Continuing to refer to  FIGS. 2A and 2B , the first waterproof housing  14  may have a sensor opening  58  through which the reflected infrared sensor  32  is exposed to the skin of the user. The dimensions of the sensor opening  58  may be the same as the dimensions of the area of the sensor  32  that is exposed to the skin. The reflected infrared sensor  32  is entirely disposed within the first waterproof housing  14 , whereas the reflected infrared sensor  32  may be substantially coterminous with the sensor opening  58 . Because the reflected infrared sensor  32  may be composed of a nonconductive waterproof material, such as Teflon, the sensor opening  58  and at least part of the reflected infrared sensor  32  may be exposed to the water and in direct contact with the skin (as shown in  FIG. 2A ), or the reflected infrared sensor  32  may be covered by a thin layer  64  of insulation material that allows the transmission of infrared light therethrough, such as silicone  59  (as shown in  FIG. 2   b ). A gasket  60  (such as a typical rubber O-ring) may be included inside the first waterproof housing  14 , between the reflected infrared sensor  32  base and the first surface  48   a  of the first waterproof housing  14 , to prevent the entry of water into the housing. Additionally, a portion of the first surface  48   a  surrounding the outer perimeter of the sensor opening  58  may be covered in a waterproof, opaque material with a relatively high coefficient of friction on skin (approximately 0.3 to 1.0μ), such as rubber. This outer perimeter may help ensure maximum contact and stability between the reflected infrared sensor  32  and the user&#39;s skin, thereby increasing the accuracy of the reflected infrared sensor  32 &#39;s measurements. For simplicity, the area of the first surface  48   a  of the first waterproof housing  14  is referred to herein as the rubber pad  62 , even though it may be composed of a different material. 
     Referring now to  FIG. 3 , a second embodiment of the biofeedback device  10  is shown. In this embodiment, the heart rate measuring apparatus  30 , power source  39 , and one or more wires  18  are entirely disposed within the frame of the goggles  12 . The frame of the goggles  12  may be waterproofed like the first and second waterproof housings  14 ,  16  shown in  FIGS. 1 ,  2 A, and  2 B and discussed above. The frame of the goggles  12  may include a first arm  64   a  and a second arm  64   b , each arm having a strap attachment means  66  at the terminus. The strap attachment means  66  may comprise a metal or plastic cap and loop through which the head strap  26  may be secured; however, any type of strap attachment means may be used that will securely couple the head strap  26  and goggles  12 . The first arm  64   a  and the second arm  64   b  each have a first surface  68   a ,  70   a  and a second surface  68   b ,  70   b , each first surface  68   a ,  70   a  being in contact with the user&#39;s head. The heart rate measuring apparatus  30  and the power source  39  may be in electrical communication with each other via one or more wires  18  disposed within a channel defined by the frame of the goggles  12  (if wireless communication is not used). The heart rate measuring apparatus  30  may be entirely disposed within the first arm  64   a  of the goggles  12 , except that the reflected infrared sensor  32  may be exposed to the water or user&#39;s skin through an opening  61  on the first surface  68   a  of the first arm  64   a . Similarly, the one or more buttons  37 , display screens  38 , or other user control features of the user interface  36  are located on the second surface  90   b  of the first arm  64   a , where they are accessible to the user. The power source  39  may be entirely disposed within the second arm  64   b  of the goggles  12 . It is understood, however, that the user interface  36  and heart rate measuring apparatus  30  may be alternatively disposed within the second arm  64   b , and the power source  39  may be disposed within the first arm  64   a.    
     Continuing to refer to  FIG. 3 , the user input may alternatively be located on a remote device  72  in wireless communication with the microcontroller  34  of the heart rate measuring apparatus  30 . Thus, the heart rate measuring apparatus  30  in this alternative embodiment may comprise the reflected infrared sensor  32  and microcontroller  34 , but not the user interface  36 . Including the user interface  36  in a separate from the goggles  12  may allow for a more streamlined design of the biofeedback device  10 , as seen in  FIG. 4 . The remote device  72  may include one or more buttons  37 , display screens  38 , and other user control elements. The user would enter into the remote device  72  age, weight, target heart rate, workout time, and other data useful in calculating calories burned, workout time, stroke pacing, and other parameters. Additionally, the user interface  36 , either disposed within the biofeedback device  10  or remote device  72 , could be used for selecting or creating a desired training program. The remote device  72  would wirelessly transmit this data (such as by WiFi, infrared, or Bluetooth® signal) to the microcontroller  34  of the heart rate measuring apparatus  30 , which would, in turn, operate the one or more signal elements  28  accordingly (e.g., color of light and/or pace of blinking of LEDs  29 ). The remote device  72  may include therein a power source  39  that may be rechargeable or single use, for example a small battery such as a hearing aid or watch battery (button cell), and may be waterproof like the first and second waterproof housings  14 ,  16  shown in  FIGS. 1 ,  2 A, and  2 B, and discussed above. It should be understood that the remote device configuration may be used with either the integrated or non-integrated heart rate measuring apparatus design (for example, either the biofeedback device  10  of  FIG. 1  or the biofeedback device of  FIG. 3 ). 
     Referring now to  FIG. 4 , an inside view of the first arm  64   a  of the goggles  12  is shown. The first surface  68   a  of the first arm  64   a  is shown, which includes an opening  61  through which the reflected infrared sensor  32  may be exposed to the user&#39;s skin. The reflected infrared sensor  32  may be composed of waterproof materials and therefore may be exposed to the water and in direct contact with the user&#39;s skin; however, the reflected infrared sensor  32  may alternatively be covered by a thin layer  64  of insulation material that allows the transmission of infrared light therethrough without distorting the infrared signal (as shown in  FIG. 2   b ). 
     Referring now to  FIG. 5 , a cross section of the reflected infrared sensor  32  is shown, which may or may not be drawn to scale. The reflected infrared sensor  32  may comprise an infrared emitter  74  (photodiode), an infrared receiver  76  (phototransistor), and sensor base  78  having a first end  80   a  and a second end  80   b , the sensor base  78  defining a shield element  81  to prevent the possible interference between the emitted and received infrared signals (i.e. to prevent the infrared light emitted from the infrared emitter  74  from directly entering the infrared receiver  76  without first being reflected from the target reflection point  84 ). The shield element  81  may be any size and shape sufficient to prevent the infrared signal interference, such as triangular shape. The reflected infrared sensor  32  may be composed of a nonconductive material, such as Teflon, to prevent interference with the current in the infrared emitter  74  and infrared receiver  76 . Additionally, the material may be opaque and non-reflective in order to block any light that can interfere with the infrared light emitted by the infrared emitter  74  and/or distort the signal received by the infrared receiver  76 . For simplicity, the term “reflected infrared sensor” used herein includes the infrared emitter  74 , infrared receiver  76 , and shield element  81 . The reflected infrared sensor  32  may be placed in contact with the user&#39;s skin; the temporal artery is located approximately 5 mm beneath the skin of the temple. 
     Continuing to refer to  FIG. 5 , the cross-sectional view of the reflected infrared sensor  32  may resemble the letter “W.” The infrared emitter  74  may be positioned at a first angle  82   a  measured in relation to an axis running from the first end  80   a  of the sensor base  78  to the second end  80   b  of the sensor base  78 , and the infrared receiver  76  may be positioned at a second angle  82   b  measured in relation to said axis. Further, the infrared emitter  74  and the shield element  81  may define a third angle  82   c , and the shield element  81  and the infrared receiver  76  may define a fourth angle  82   d . The reflected infrared sensor  32  configuration may be determined for any target reflection point  84 . For example, the angle between the infrared emitter  74  and the shield element  81  may be set at 45 degrees. Next, a point 5 mm from the outer edge of the infrared emitter  74  may be used as the reflection point because the temporal artery is located an average of 5 mm beneath the skin of the temple (as shown in  FIG. 5 ). Then, the distance between the infrared emitter  74  and infrared receiver  76  may be adjusted until an oscilloscope measurement of the infrared signal is of the highest amplitude, which means the location of the infrared receiver  76  would ensure optimal receipt of the infrared light. The degree of emission (the fifth angle  82   e ) of the infrared light from the infrared emitter  74  may also be determined, based on the relative positions of the infrared emitter  74 , infrared receiver  76 , and the target reflection point  84 . 
     Referring now to  FIGS. 6A ,  6 B, and  6 C, the reflected infrared sensor  32  may be adjusted by the user horizontally (along an x-axis), vertically (along a y-axis), or a combination of horizontally and vertically to a distance of, for example, 1 cm. Since there are minimal variations between the location of the temporal artery between one person and another, the reflected infrared sensor  32  may be mounted within the waterproof housing (either in, for example, the first waterproof housing  14  or the first arm  64   a  of the goggles  12 ) in such a way that allows for the positioning of the reflected infrared sensor  32  by tightening or loosening one or more screws  52 , while still preventing the entry of water into the waterproof housing. If the reflected infrared sensor  32  does not detect the user&#39;s heart rate, the one or more signal elements  28  will not broadcast a visual, auditory, or tactile heart rate signal to the user, but may instead emit a blinking red light. In this case, the user may adjust the reflected infrared sensor  32  until heart rate is detected. Unlike other heart rate measuring devices, the reflected infrared sensor  32  may not be easily repositioned by repositioning the entire device  10 , because the goggles  12  must be fitted over the eyes of the user and thus may not be able to accommodate movement of a fixed sensor. Exemplary methods of adjusting the reflected infrared sensor are shown in  FIGS. 6A ,  6 B, and  6 C. 
       FIG. 6A  shows a cross-sectional view of the first waterproof housing  14  with a panel-type sensor adjustment mechanism  86 . The reflected infrared sensor  32 , or a plurality of reflected infrared sensors  32 , may be coupled to the panel-type sensor adjustment mechanism  86  by one or more screws  52  that may be screwed into any of a plurality of screw holes  88  located on the surface  90  of the panel-type sensor adjustment mechanism  86 . The screw holes  88  may terminate at least partially through, but do not continue all the way through, the panel-type sensor adjustment mechanism  86 , which prevents water from entering the first waterproof housing  14 . The panel-type sensor adjustment mechanism  86  may be coupled to the first waterproof housing  14  such that only the outer rim  92  of the panel-type sensor adjustment mechanism  86  may be flush with the first surface  48   a  of the first waterproof housing  14 , with the surface  90  of the panel-type sensor adjustment mechanism  86  being recessed. Similarly, the portion of the reflected infrared sensor  32  that is in contact with the skin may be substantially coplanar with the first surface  48   a  of the first waterproof housing  14 . 
     Referring now to  FIG. 6B , the panel-type sensor adjustment mechanism  86  may be adjusted horizontally (along an x-axis), vertically (along a y-axis), or a combination of horizontally and vertically by unscrewing the one or more screws  52  from any of a plurality of screw holes  88 , moving the reflected infrared sensor  32  along the surface  90  of the panel-type sensor adjustment mechanism  86 , and replacing the one or more screws  52  into the corresponding one or more screw holes  88 . The sensor base  78  may also have one or more flanges  87  having one or more screw holes  88  that align with the one or more screw holes  88  on the surface  90  of the panel-type sensor adjustment mechanism  86 . The entire surface  90  and outer rim  92  of the panel-type sensor adjustment mechanism  86  are waterproof and may be exposed to water. 
     Alternative or additional to the method of adjusting the reflected infrared sensor  32  shown in  FIGS. 6A and 6B , a spiral-type sensor adjustment mechanism  94  may be included. In the spiral-type sensor adjustment mechanism  94 , reflected infrared sensor  32  may or may not be coupled to a surface having a plurality of screw holes  88 . Instead, the infrared sensor  32  may be coupled to an adjustment plate  97  disposed within the first waterproof housing  14 . The sensor base  78  may include one or more feet  98  that may be in contact with a shaft  98  having a spiraled threading  100  (for example, a screw). The one or more feet  96 , the shaft  98 , and the spiraled threading  100  may be entirely disposed within the first waterproof housing  14 . Coupled to one end of the shaft  98  may be a knob  102 , which is not disposed within the first waterproof housing  14 , but is instead accessible to the user. When the user turns the knob either clockwise or counterclockwise, the spiraled threading  100  engages the feet  96  to move the reflected infrared sensor  32  along either the x-axis or the y-axis (for example, to a distance of 1 cm from the centerpoint in either direction), depending on the axis on which the spiral-type sensor adjustment mechanism  94  is disposed. It is understood that the sensor adjustment mechanisms  86 ,  94  of  FIGS. 6A-6C  could be similarly disposed within other waterproof housings, for example, the first arm  64   a  of the goggles  12 . 
     Referring now to  FIGS. 7A and 7B , the one or more signal elements  28  are shown.  FIG. 6A  shows a continuous rope of clear tubing with multiple LEDs  29  therein  29   a , and  FIG. 7B  shows discrete LEDs  29   b . The clear tubing may contain one or more LEDs  29 , and is referred to herein as a “rope-type LED light”  29   a . Each eye cup  20   a ,  20   b  includes a lens  22   a ,  22   b , which is the surface of the eye cup that is disposed directly in front of the user&#39;s eye. The rope-type LED light  29   a  may be at least partially disposed about the inner circumference of at least one of the first and second eye cups  20   a ,  20   b  either adjacent to or on the lens  22   a ,  22   b . Included in the first eye cup  20   a  is a first lens  22   a , and included in the second eye cup  20   b  is a second lens  22   b.    
     The rope-type LED light  29   a  may be entirely disposed about a circumference of at least one of the first and second lenses  22   a ,  22   b . For example,  FIG. 7A  shows the rope-type LED light  29   a  disposed about the entire inner circumference of the first eye cup  20   a . Alternatively, the rope-type LED light  29   a  may be disposed within or underneath at least one of the first and second eye cup gaskets  24   a ,  24   b , at least partially disposed about the inner circumference of the eye cup  20   a ,  20   b  where the eye cup  20   a ,  20   b  is coupled to the eye cup gasket  24   a ,  24   b . Depending on the placement of the rope-type LED light  29   a , the user may either perceive a direct light or an indirect light. When the rope-type LED light  29   a  is disposed within at least one of the first and second eye cup gaskets  24   a ,  24   b , the light may be a diffuse light that is reflected from the inside of the eye cup  20   a ,  20   b  and may give the effect of illuminating the entire eye cup with color. No matter what the placement of the rope-type LED light  29   a , the user should be able to perceive the color and/or blinking of the light without undue effort. 
     Continuing to refer to  FIG. 7B , one or more discrete LEDs  29   b  are shown. The discrete LEDs  29   b  may be located at any position about the inner circumference of at least one of the first and second eye cups  20   a ,  20   b , either adjacent to or on the first and/or second lens  22   a ,  22   b . Any number of discrete LEDs  29   b  may be used. The discrete LEDs  29   b  may be equidistant from one another, or they may be grouped together at any point in the first and/or eye cup  20   a ,  20   b . Alternatively, the discrete LEDs  29   b  may be disposed within or underneath at least one of the first and second eye cup gaskets  24   a ,  24   b  (as shown in  FIG. 7B ). Depending on the placement of the discrete LEDs  29   b , the user may either perceive a direct light or an indirect light. When the discrete LEDs  29   b  are disposed within at least one of the first and second eye cup gaskets  24   a ,  24   b , the light may be a diffuse light that is reflected from the inside of the eye cup  20   a ,  20   b  and may give the effect of illuminating the entire eye cup with color. No matter what the placement of the discrete LEDs  29   b , the user should be able to perceive the color and/or blinking of the light without undue effort. 
     Referring now to  FIGS. 8A and 8B , the one or more signal elements  28  may alternatively be coupled to or housed in a positionable element  103  that the user may place in any desired position on the biofeedback device  10 . Such a housing may have such attachment means as a clip, adhesive junction, suction cup, malleable arm coupled to the goggles, or any other suitable means. For example,  FIG. 8A  shows the goggles  12  having an eye cup track  104  that may be disposed at least partially about the circumference of the outer surface  106  of one or both eye cups  20   a ,  20   b . The one or more signal elements  28  may be removably coupled to the eye cup track  104 , such as by a clip.  FIG. 9B  shows the one or more signal elements  28  coupled to a suction cup  108  that may be removably attached to the outer surface  106  of one or both eye cups  20   a ,  20   b . Regardless of the type of positionable element  103  used, the positionable element  103  may be in electrical communication with the power source  39  and microcontroller  34  via one or more flexible wires  18  that may be at least partially disposed on the outside of the goggles  12  (not within a waterproof housing). 
     Referring now to  FIG. 9 , an exemplary communication scheme of the one or more signal elements  28  is shown. In  FIG. 9 , a visual signal element is contemplated, specifically, an LED display. Three colors of LEDs  29  may be used to represent the three training zones (weight loss, fitness, and maximum performance). It is understood that more colors may be used, depending on the number of training zones to be represented. Additionally, the LEDs  29  may emit a steady light only, or may emit a steady light or a blinking light to represent upper and lower ends of the represented training zones. The LEDs  29  may emit a blinking red light if the reflected infrared sensor  32  does not detect a heart rate. The presence of a blinking light will communicate to the user that the unit has sufficient power, but that the sensor is not in the optimal location for detecting heart rate. Further, the color of the light and its status (blinking or steady) easily communicate heart rate to the user without requiring the user to read small numbers or pause swimming to look at a watch or similar device. 
       FIG. 9  shows an example of this system: after a boot up sequence  110 , the user may enter data into the user interface  36  (such as age, weight, or desired workout program), the process referred to as “user data entry”  112 . The heart rate measuring apparatus  30  may then detect and measure the user&#39;s heart rate, and the user may manually adjust the position of the reflected infrared sensor  32  if no heart rate is detected. This process is referred to as “heart rate detection and adjustment”  114 . After heart rate detection and measurement  114 , heart rate measuring apparatus  30  may then compare the user&#39;s heart rate to the user&#39;s target heart rate and communicate the result to the one or more signal elements  28 , a processed referred to as “comparison and display”  116 . 
       FIG. 9  also shows an exemplary comparison and display  116  process, in which the weight loss zone is typically a heart rate of 50% to 70% of the maximum heart rate, and may be represented by one or more green LEDs  29 . The green LEDs  29  may blink slowly in the 50% to 55% range (lower end of the zone), may glow steadily in the 55% to 65% range (middle of the zone), and may blink quickly in the 65% to 75% range (upper end of the zone). The fitness zone is typically a heart rate of 70% to 85% of the maximum heart rate, and may be represented by one or more yellow LEDs  29 . The yellow LEDs  29  may blink slowly in the 70% to 75% range (lower end of the zone), may glow steadily in the 75% to 80% range (middle of the zone), and may blink quickly in the 80% to 85% range (upper end of the zone). The maximum performance zone is typically a heart rate of 85% of the maximum heart rate and above, and may be represented by one or more red LEDs  29 . The red LEDs  29  may glow steadily in the 85% to 90% range (lower end of the zone), and may blink slowly at heart rates above 90% of the maximum heart rate (middle and upper end of the zone). Depending on the LEDs  29  used, any number of color options may be available for a single LED bulb (such as when multi-color LEDs  29  are used, or when the signal display element comprises multiple LEDs  29  of various colors). The user interface  36  may include a means by which the user may adjust the LED display correlated to heart rate. For example, the user may prefer blue LEDs  29  for the weight loss zone, red LEDs  29  for the fitness zone, and green LEDs  29  for the maximum performance zone. Additionally, the user may also use the user interface  36  to specify a steady LED glow without blinking, or may desire to set the speed of the blinking to match a target swim stroke pace. 
     It should be understood that the microcontroller  34  may measure and record other types of biofeedback data in addition to heart rate, and may also be able to measure non-biofeedback data. For example, the microcontroller  34  of the biofeedback device  10  may additionally comprise circuitry for performing the functions of a chronometer, timer, lap counter, distance measurement device, calorie counter, blood oximeter, and wireless transmitter (such as a Bluetooth® device). 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.