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Aerobic moderate to vigorous physical activity (MVPA) performed in the evening is associated with lower risks for mortality, cardiovascular disease (CVD), and microvascular disease among individuals with obesity, according to study results published in Diabetes Care. Numerous randomized controlled trials have shown a link between glycemic control benefits and aerobic exercise in the late afternoon or evening compared with the morning. However, it is not clear whether the timing of aerobic MVPA is linked to long-term outcomes such as morbidity and mortality among individuals with obesity or type 2 diabetes. To investigate the association between timing of MVPA and CVD and mortality outcomes, researchers sourced data from the UK Biobank accelerometry substudy. Participants with obesity, including those with type 2 diabetes, were enrolled between 2006 and 2010. The researchers defined aerobic MVPA as lasting at least 3 continuous minutes. Physical activity was measured via an Axivity AX3 accelerometer that participants wore around their wrist for a full week. Participants were stratified according to morning (6 am-12 pm), afternoon (12 pm-6 pm), and evening (6 pm-12 am) MVPA, along with a reference group that had less than 1 aerobic MVPA bout per day. The primary outcomes were all-cause mortality, CVD incidence, and microvascular disease (nephropathy, neuropathy, and retinopathy) incidence. " The results of this study emphasize that beyond the total volume of MVPA, its timing, particularly in the evening, was consistently associated with the lowest risk of mortality relative to other timing windows. The study sample for all-cause mortality included 29,836 participants (mean age, 62.2 years), of whom 53.2% were women, 46.8% were current or previous smokers, and 2995 had a type 2 diabetes diagnosis at baseline. The sample for CVD included 24,660 participants, whereas the sample for microvascular disease included 28,455 participants. After an average follow-up of 7.9 years, the all-cause mortality risk was lowest among the evening MVPA group (hazard ratio [HR], 0.39; 95% CI, 0.27-0.55) compared with the reference group. Participants in the afternoon (HR, 0.60; 95% CI, 0.51-0.71) and morning (HR, 0.67; 95% CI, 0.56-0.79) MVPA groups exhibited similar mortality risks. The evening MVPA group also showed the lowest risk for CVD incidence (HR, 0.64; 95% CI, 0.54-0.75). For microvascular incidence, the risk reduction was similar across all timed activity groups. Among participants with obesity and type 2 diabetes, evening MVPA was associated with the lowest mortality risk (HR, 0.24; 95% CI, 0.08-0.76) and CVD incidence risk (HR, 0.54; 95% CI, 0.34-0.86). Study limitations include the potential for reverse causation, a median lag of 5.5 years between the UK Biobank baseline and the accelerometry study, and a low response rate in the UK Biobank. The researchers concluded, "The results of this study emphasize that beyond the total volume of MVPA, its timing, particularly in the evening, was consistently associated with the lowest risk of mortality relative to other timing windows."