Recent research suggests that doing moderate-to-vigorous aerobic exercise in the evening may confer the greatest protection against mortality, cardiovascular disease (CVD), and microvascular disease (MVD) among adults with obesity, including those who also have type 2 diabetes (T2D).
Background & Methods
We already know that bouts of moderate to vigorous aerobic physical activity (MVPA) help improve cardiometabolic health. What’s less clear is whether doing that activity in the morning, afternoon, or evening yields the greatest long-term benefit.
To explore this, investigators tapped into UK Biobank data involving 29,836 adults with obesity (body mass index ≥ 30; average age ~62.2 years; 53.2% women). Among them, 2,995 had T2D.
Aerobic activity was defined as continuous bouts lasting at least 3 minutes. Intensities (light, moderate, vigorous) were derived from accelerometer data.
Participants were classified into three groups based on when more than 50% of their MVPA occurred:
Morning (6 AM to <12 PM)
Afternoon (12 PM to <6 PM)
Evening (6 PM to <12 AM) Those who did no qualifying aerobic bouts served as the reference group.
Over a median follow-up period of 7.9 years, the researchers examined associations between the timing of MVPA and the risk of (1) all-cause mortality, (2) CVD (broadly circulatory conditions), and (3) microvascular disease (retinopathy, nephropathy, neuropathy).
Key Findings
The evening MVPA group had the lowest mortality risk (hazard ratio [HR], 0.39; 95% CI, 0.27–0.55) relative to the reference group. In the subgroup with T2D, the benefit was even more striking (HR, 0.24; 95% CI, 0.08–0.76).
Morning (HR, 0.67; 95% CI, 0.56–0.79) and afternoon (HR, 0.60; 95% CI, 0.51–0.71) activity also reduced mortality risk compared to the reference group—but those associations were weaker than for evening activity.
The evening exercisers also showed lower incidence of CVD (HR, 0.64; 95% CI, 0.54–0.75) and MVD (HR, 0.76; 95% CI, 0.63–0.92) versus the reference.
Among the participants with obesity plus T2D, evening MVPA was linked consistently to lower risks for death, cardiovascular disease, and microvascular complications.
Practical Implications
The authors conclude:
“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.”
In other words, if you have flexibility in when you exercise, it may be advantageous, especially if you’re managing obesity or T2D, to aim for later in the day. That said, activity at any time is better than none, and individual preferences, lifestyle constraints, and sleep schedules should also guide your choices.
Source:
The study, led by Angelo Sabag, PhD, Charles Perkins Centre, The University of Sydney, Sydney, was published online in Diabetes Care.
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