What is the Metabolic Cost of Sitting, Standing, and Sit/Stand Transitions? A Randomized Controlled Trial

Detailed Summary

There is already a lot of scientific evidence supporting the benefits of public health recommendations regarding physical activity (the accumulation of at least 150 minutes of at least moderate intensity physical activity per week). However, these 30 daily minutes represent only about 3% of the waking period. Recent data suggest that most of the population spends on average 8-9 hours / day of sedentary behavior (SB). SB is characterized by any activity with a metabolic cost (MC) below 1.5 METs, mainly actions in the sitting position. In fact, there is evidence that the more time spent sitting higher the risk of disease and mortality, with sitting directly associated with diseases such as type II diabetes, cardiovascular diseases and even cancer. The average life expectancy may increase by \~ 2 years if the investigators reduce sitting about 3h/ day. Additionally, how people accumulate sitting time seems to be a major factor, with prolonged sitting associated with a higher risk of disease. Short-term experimental studies indicate that sedentary lifestyles affect energy balance enhancing weight gain. While there is some research regarding the MC associated with "sitting" and "standing" behaviors, the results are contradictory. Besides these conflicting results, the impact of transitions between these two types of behavior and how these transitions can contribute to MC increase have never been investigated. Our hypothesis is that, in both men and women, the simple replacement of sitting for "standing" may not substantially increase MC, but instead, the largest contribution may reside on the transitions between these two states of behavior. Therefore, the investigators will perform a study with the following purposes: Examine MC and HR associated with "sitting", "standing", and transitions between these two types of behavior in adults of both gender, apparently healthy with variable body composition profiles.

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