Using basic data from the Look AHEAD study, the researchers wanted to characterize the temporal distribution of combat-related MVPA in adults with overweight / obesity and T2D, define whether timing varies depending on socio-demographic or anthropometric factors, and determine associations at the time of the fight. Related MVPA with basic cardiorespiratory fitness and risk of coronary artery disease (CHD).
The Look AHEAD study randomized adults (n = 5145) with overweight / obesity and T2D to an intensive lifestyle intervention or a diabetes support and education program. All participants in the current analysis (n = 2035) completed the basic tests before randomization, were diagnosed with T2D, and had a body mass index (BMI) of at least 25 kg / m2 (or ≥27 kg / m2 if taking Insulin). and were between 45 and 76 years old.
Throughout the study period (1 week), participants were instructed to wear the RT3 triaxial accelerometer on their hip for seven consecutive days during waking hours and to remove it only for sleep, bath, shower, or other water-based activities. and they have been instructed not to change their usual PA patterns while wearing the device.
Determination of the intensity of physical activity (expressed in metabolically equivalent tasks [METs]) the researchers divided the estimated energy consumption per minute by the estimated idle energy consumption per minute calculated by the software.
“MVPA periods were defined as ≥3 MET. Combat-related MVPA was defined as any activity with ≥ 3 METs and a duration of ≥ 10 minutes, allowing a 1 to 2 minute interruption of the MVPA, ”the authors wrote. In addition, participants were divided into 6 groups based on the time of day, with the majority of combat-related MVPA (MET × min) being ≥ 50% of the combat-related MVPA in the same time window (morning, noon, afternoon). or in the evening), <50% combat-related MVPA in each time category (mixed; reference group) and ≤ 1 day with combat-related MVPA per week (inactive). "
- Cardiorespiratory fitness was highly associated with timing of combat MVPA (P = 0.0005) regardless of weekly combat MVPA volume and intensity, while the association varied by gender (P = 0.02).
- In men, the lunch group had the least fitness (β = -0.46; 95% CI, -0.87 to -0.06), while the mixed group was least fit in women.
- The Framingham Risk Score (FRS) was associated with the timing of the combat-related MVPA (P = 0.02), which also differed by gender (P = 0.0007).
- The male morning group had the highest 4-year FRS (2.18%; 95% CI, 0.70% -3.65%), but no association was observed in women.
Overall, men who did the majority of the combat-related MVPA at noon had the lowest cardiorespiratory fitness, the authors wrote. In comparison, men who were most active in the morning hours tended to have the highest cardiorespiratory fitness. In addition, men who did most of the combat-related MVPA in the morning hours had a higher 4-year FRS, which indicates a higher chance of developing CHD over the next 4 years regardless of their overall combat-related MVPA and strength the MVPA fight intensity and their cardiorespiratory fitness, ”the researchers noted.
This finding could be due to the fact that men at higher risk are more likely to do MVPA in the morning. Other factors such as time of ingestion, length of sleep, or type of occupation may have contributed to this finding, but were not measured in the current analysis.
“The general message to our patient population remains that you should exercise whenever you can, as regular exercise offers significant health benefits,” study author Jingyi Qian, PhD said with additional consideration so that we can provide better recommendations to the public on how The time of day can affect the relationship between exercise and cardiovascular health. “
The results are consistent with the evidence for the relationship between the circadian system and exercise physiology. However, it is unclear why time-specific activities can be associated with different health conditions.
“Interest in the interaction between physical activity and the circadian system is still emerging,” said Qian. “We developed a method of quantifying and characterizing participants based on the time of their physical activity that allows researchers to conduct other studies on other cohorts.”
Future longitudinal studies are needed to further investigate the relationship between timing of combat-related MVPA and improvement in cardiorespiratory fitness and potential mechanisms, the authors concluded.
Qian J., Walkup MP, Chen S. et al. Association of the objectively measured timing of physical activity struggles with cardiovascular health in type 2 diabetes. Diabetes treatment. Published online February 17, 2021. doi: 10.2337 / dc20-2178