Individual Variability to Aerobic Exercise Training
Condition: Cardiovascular Disease
MeSH terms: Cardiovascular Diseases
Study type: Interventional

Summary: 
      The purpose of this study is to: 1) determine the cohort specific technical error to use in
      the categorization of response rate; 2) determine if an individualized intensity prescription
      is superior to a standard approach in regards to VO2max and cardiometabolic risk factor
      responsiveness; 3) Investigate the time course changes throughout 12 weeks of CRF training
      between an individualized and standardized exercise prescription; and 4) determine if
      non-responders can become responders if the exercise intensity prescription is modified.

      It is hypothesized that:

        1. The individualized method will elicit a greater responsiveness for all measurements when
           compared to the standardized method.

        2. There will be a greater amount of non-responders in the standardized group (based on
           changes in VO2max).

        3. When participants in the standardized group are considered non-responders and change
           their exercise prescription to the individualized group, they will become a responder
           (based on changes in VO2max)
    

Detailed description: 
      It has generally been accepted there is individual variability to cardiorespiratory fitness
      (CRF) training. However, the underlying cause of the variability is not well understood.
      Traditionally, a standardized approach to exercise prescription has utilized relative
      percentages of maximal heart rate (HR), HR reserve (HRR), maximal oxygen consumption
      (VO2max), or VO2 reserve to establish exercise intensity. This 'one size fits all' model
      fails to take into consideration individual metabolic responses to exercise and may be
      related to the variability in training responses.

      An individualized exercise prescription utilizing a threshold-based training model (i.e.
      ventilatory threshold) would help consider individual metabolic responses to exercise
      training. However, minimal research has been conducted to differentiate between the
      standardized and individualized methods. Therefore, a randomized control trial within a
      community-based wellness program will be implemented to investigate the following research
      question: does an individualized exercise prescription decrease the incidence of non-response
      to CRF and cardiometabolic measurements compared to the standardized approach? The criteria
      to determine the incidence of response will be set based on the biological variability and
      measurement error determined during baseline testing.

      A secondary outcome of the study will be investigating the time course changes in response to
      12 weeks of individualized and standardized exercise prescription. Currently, minimal
      research exists on the effects of differing exercise prescription and the time course changes
      with the reporting of individual data.

      Many experimental trials are conducted in a very controlled and supervised environment and
      may lack real world application. This investigation would occur in a community-based wellness
      program to encourage a 'real-world' application. Results of this study would enhance the
      ability of exercise physiologists to prescribe exercise to the individual, rather than a 'one
      size fits all' model. This would be the first study to investigate individualized versus
      standardized exercise prescription with an isocaloric exercise volume.

      Therefore, sedentary men and women (n = 40) will be randomized to one of two experimental
      groups - individualized or standardized. There will be a separate control group (n = 20) that
      is recruited from the community that has the same inclusion criteria as the experimental
      group. Exercise training will be performed 3 days a week with weekly energy expenditure
      progressively increasing from 5.6 to 15.4 kcal/kg/week for 12 weeks with one of two exercise
      intensity regimens: 1) a standardized method based on percentages of HRR, or 2) a threshold
      based method with the use of the first (VT1) and second ventilatory threshold (VT2).
      Participants will undergo testing (anthropometric measures, blood profile, and maximal
      exercise test) at baseline, 4 weeks, 8 weeks, and 12 weeks.

      Following the 12 week intervention, participants will be categorized as a responder or
      non-responder based on overall changes in VO2max. For responders, they will be done with the
      intervention. However, non-responders will be asked to complete a second 12 week intervention
      in the other experimental group (i.e. a non-responder in the standardized group will now
      complete a 12 week intervention the individualized group. The exercise prescription and
      progression will be the same for the second 12 weeks.
    

Intervention name(s): Exercise
Intervention type(s): Other
Intervention description(s): Continuous aerobic exercise prescribed according to two exercise intensity methods: individualized (i.e. ventilatory threshold) and standardized (i.e. heart rate reserve)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Prevention
Keywords: primary prevention