FIT 2 SIT - Are Metabolic Responses to Sitting/Light Breaks Mediated by Fitness?
Condition: Diabetes
Study type: Interventional

Summary: 
      The purpose of this study is to determine whether an individuals cardio-respiratory fitness
      level can protect them from the negative metabolic impacts of prolonged sitting time.

      Overall, it is hypothesised that in individuals with high fitness, the unfavourable effect of
      prolonged sitting (build up of sugar, fat and insulin in the blood following a meal) will not
      be as substantial, nor will light activity breaks be as advantageous, compared to individuals
      with lower fitness as they have a smaller scope for metabolic improvement.
    

Detailed description: 
      The FIT 2 SIT study requires three separate study visits in total.

      At visit one, we will check the participants blood pressure, height, weight, waist
      measurement and body fat percentage, we will also take a blood sample to measure HbA1c and
      cholesterol, all of which will help confirm that this participant is eligible to continue in
      this study (some may be excluded based on results of the above). We will also measure the
      amount of energy participants expend per minute while at rest and during a slow walking task
      (3km.h on a treadmill) using a gas mask technique. Energy responses to sitting and walking
      differ between individuals, therefore it is of interest to observe how each participant in
      this study responds to these conditions as it may help explain any potential findings of this
      study. For instance, introducing walking breaks (by way of reducing sitting time) may only
      benefit those who have consequent increases in energy expenditure as a result of these
      breaks. Lastly, to mark the end of the first study visit, participants will be asked to
      perform an exercise test based on a treadmill to assess their fitness level. whilst running a
      special mask covering the nose and mouth will be worn to analyse breathing, this will be
      connected to a machine (gas analyser) that gives information on the amount of oxygen
      participants breathe in and out. The point at which the amount of oxygen they breathe in
      remains stable despite increases in exercise difficulty is the point that we will stop the
      exercise test because this tells us that they have reached their exercise capacity (called
      V02max), and from this we can determine fitness level.

      Following this first visit we will have fitness level data from all participants. Recruiting
      participants with a diverse fitness level will then help to elucidate the role that an
      individuals fitness has on their response to the following treatment conditions.

      Treatment condition A is referred to as the 'sitting' condition. Here participants will
      remain seated throughout the whole of the 7 ½ hour test period (8am - 3:30pm) whilst watching
      TV/DVD's, reading, using the internet, doing paperwork etc. at their will. On arrival,
      participants will have a cannula (a small tube that allows us to take blood) inserted into
      their arm; this will stay in the arm and allow us to take regular blood samples throughout
      the day, without the need for multiple needles. After we take the first blood sample,
      participants will sit quietly for an hour. We will then provide breakfast. Whilst sitting, we
      will take blood samples (using the cannula) and blood pressure at 30, 60, 120 and 180 minutes
      after breakfast. We will then provide a lunch meal and will continue taking blood samples and
      blood pressure at 30, 60, 120, 180 and 210 minutes after this lunch meal. In total, we will
      take 11 blood samples over the 7 ½ hour testing period. Although this may sound a lot, it is
      equivalent to around 8-9 teaspoons of blood over the course of the day.

      Condition B is the 'light activity breaks' condition. Participants will go through exactly
      the same process as condition A but will also be asked to do 5 minute bouts of slow walking
      on a treadmill every 30 minutes following breakfast and lunch. In total they will do 12 five
      minute walks on the treadmill throughout the 7 ½ hour test period (60 minutes of walking in
      total). In total, we will take 11 blood samples on the day.

      With data on each participants metabolic response to a meal during A) prolonged sitting and
      B) during an interrupted sitting condition, we can see how fitness influenced the results.

      However, at present, the absence of laboratory randomised crossover trials assessing the
      'extent' to which fitness moderates the relationship between sedentary behaviour and
      metabolic health markers appear absent from the literature, warranting further investigation,
      which is why this design was chosen.
    

Intervention name(s): Prolonged sitting; Light activity breaks
Intervention type(s): Other; Other
Intervention description(s): Condition A is referred to as the 'sitting' condition. Here participants will remain seated throughout the whole of the 7 ½ hour test period (8am - 3:30pm). On arrival, participants will have a cannula (a small tube that allows us to take blood) inserted into their arm; this will stay in the arm and allow us to take regular blood samples throughout the day. Blood samples and blood pressure will be taken at 30, 60, 120 and 180 minutes after breakfast. We will then provide a lunch meal and will continue taking blood samples and blood pressure at 30, 60, 120, 180 and 210 minutes after this lunch meal. In total, we will take 11 blood samples over the 7 ½ hour testing period.; Condition B is the 'light activity breaks' condition. Participants will go through exactly the same process as condition A but will also be asked to do 5 minute bouts of slow walking on a treadmill every 30 minutes following breakfast and lunch. In total they will do 12 five minute walks on the treadmill throughout the 7 ½ hour test period (60 minutes of walking in total). In total, we will take 11 blood samples on the day.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention