Studies: Morning Workouts May Burn Fat More Effectively Than Evening Ones

The time of day at which a person exercises may affect how effectively the body burns fat. This is indicated by research from Sweden's Karolinska Institute and Denmark's University of Copenhagen, reported by the Estonian news portal Postimees. The findings may interest people who want to lose weight and are deciding when to train.

What the European researchers found

The study, published in the scientific journal PNAS, analysed participants' metabolic responses at different times of day. Fat metabolism is the rate at which the body uses fat to produce energy. A workout in the early active phase, which for humans corresponds to late morning, activated fat burning and metabolic processes considerably more strongly than an evening workout.

The increase in fat burning was not linked to what participants ate before exercising. According to the scientists, this suggests that the body's internal biological clock largely determines how it responds to physical exercise.

The US study

These conclusions are supported by work from researchers at Skidmore College in New York. Over 12 weeks they tracked the exercise and eating habits of men and women, who were split into two groups: one trained from 6:30 to 8:30 a.m., the other in the evening from 6:00 to 8:00 p.m.

Among women, morning workouts proved better suited to those who wanted to reduce fat around the stomach and thighs. Early physical activity was also found to help build leg and glute muscles more effectively.

Conclusion

The scientists acknowledge that the effect of time of day on training results still needs further study. Still, if weight does not drop, it is not always necessary to increase the workload — sometimes it is enough to move a workout from the evening to an earlier time.