Exercise Timing and Heart Health

If you’re working out regularly yet not witnessing the expected improvements in heart health, it might not be your routine but rather the timing of your workouts that’s at fault.

Recent research in the journal Open Heart revealed that individuals who aligned their exercise schedules with their natural body rhythms, or chronotypes, experienced notable enhancements in blood pressure, cholesterol, and sleep quality compared to those who did not.

The study involved over 130 adults aged 40 to 60, all having at least one cardiovascular risk factor, such as high blood pressure, excess weight, or a sedentary lifestyle.

Researchers determined each participant’s chronotype using a questionnaire and monitoring core body temperature over 48 hours. They then assigned participants to exercise either in harmony with their chronotype or at a mismatched time. Everyone engaged in five 40-minute moderate aerobic sessions each week for a 12-week period.

Your chronotype refers to your circadian rhythm, influencing your sleep patterns, hormone levels, and energy throughout the day. Generally, people fall into two main categories: “morning larks,” who wake early and feel most energized in the morning, and “night owls,” who are more alert later in the day.

For this study, morning larks exercised between 8 and 11 a.m., while night owls exercised from 6 to 9 p.m. when their rhythms were most favorable.

After 12 weeks, both groups showed improvements, but those who exercised in alignment with their chronotype saw more substantial benefits across almost all measures:

• Systolic blood pressure decreased significantly more in the chronotype-matched group (10.8 mm Hg) compared to the mismatched group (5.5 mm Hg).
• Participants with high blood pressure in the matched group experienced an average decrease of 13.6 mm Hg, nearly double that of the mismatched group (7.1 mm Hg).
• Sleep quality increased by 3.4 points in the matched group, whereas it rose by only 1.2 points in the mismatched group.

Enhancements in aerobic fitness, heart rate variability, fasting glucose, and LDL cholesterol levels were also more pronounced in the chronotype-aligned participants, with morning larks showing slightly better overall improvements than night owls.

Understanding the Importance of Timing

The researchers suggest that exercising in line with your internal clock may help the body’s peripheral clocks—located in muscle, fat tissue, and blood vessels—function more effectively, thereby reducing inflammation and improving metabolic health. Both factors are closely connected to heart health.

This notion is referred to as “chrono-exercise,” which may provide a practical, drug-free strategy for preventive heart care.

Dr. Rajiv Sankaranarayanan from the British Cardiovascular Society mentioned that these findings could lead to better interventions for patients at high risk, emphasizing the potential benefits of integrating simple chronotype assessments into lifestyle recommendations. He noted:

“Incorporating simple chronotype assessment into lifestyle advice could enhance adherence and outcomes, particularly in patients with hypertension or cardiometabolic risk. … Overall, this study supports a shift toward more personalized, circadian-informed exercise prescriptions in routine cardiovascular care.”

He pointed out, however, that more extensive and varied studies are necessary before adopting this strategy in standard clinical practice.

Nonetheless, if you’re at risk for heart disease, adjusting your workout schedule based on your chronotype could make your exercise routine more beneficial.

For additional information on maintaining heart health, see “10 of the Worst Possible Foods for Your Heart Health.”