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BARCELONA — Going for a jog or pumping iron in the morning is a tall task for many night owls, but here’s one more reason to give it a shot. Exercise in the morning, such as a brisk walk or bike ride, could stave off cancer, according to a recent study.

Scientists from the Barcelona Institute for Global Health say that regular exercise early in the day boosts the body clock, which helps suppress the disease. The study of 2,795 people in Spain finds that those who were physically active between 8 a.m. and 10 a.m. in particular were less likely to develop prostate or breast tumors, respectively.

People who typically prefer staying up late benefitted the most by working out instead of staying in bed.

“The timing of physical activity obviously has an effect upon the rhythm of sex hormones and melatonin, as well as on food metabolism,” explains study coordinator Dr. Manolis Kogevinas in a statement, per SWNS. “That might explain our results.”

Interestingly, similar results were seen in men who exercised between 7 o’clock and 10 o’clock in the evening. But that result was not the same for women. Results were unchanged when considering the most strenuous physical activity timing.

Circadian rhythm may be behind the protective effects of morning exercise

So what makes the morning so crucial when it comes to exercise? Researchers explain that our bodies produce melatonin when it is dark. The chemical helps regulate sleep and affects many functions tied to the body’s 24-hour clock, or circadian rhythm. Melatonin also halts the spread of cancer and it is known that working out late or being up late slows the body’s production of it.

“One potential cause of cancer is circadian disruption, the misalignment of environmental cues such as light and food intake,” says Dr. Kogevinas. “It’s established that regular physical activity throughout lifetime can reduce cancer risk. This protective effect could be the most beneficial when physical activity is done in the morning.”

Most studies on circadian disruption tend to focus on night shift work. It’s believed exposure to artificial light and late night snacks play a role in cancer.

The latest findings are the first to identify a link between risk and the timing of exercise. The results back an experimental study which showed physical activity in the afternoon and in the evening can delay melatonin production.

“The hormone is produced mainly during the night and with well-known anti-cancer properties,” says Kogevinas. “These results, if confirmed, may improve current physical activity recommendations for cancer prevention. What is clear is that everyone can reduce their cancer risk simply by being moderately physically active for at least 150 minutes each week.”

The study is published in the International Journal of Cancer.

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