Going for a run in the morning or hitting the gym before work could help you lose almost half a stone more than if you work out later in the day, a study has found.
The two-hour window between 7am and 9am is the best for losing weight, reducing BMI and slimming the waist, data shows.
Wrist-worn activity trackers monitored the exercise levels of more than 5,000 people in the mid-noughties and found the pre-work window to be best for people wanting to shed the pounds.
People who did 150 minutes a week of moderate to vigorous activity a week were found to be around six pounds lighter.
The accelerometers worn by the participants could not tell the difference between the type of exercise but study author Dr Tongyu Ma, assistant professor of exercise physiology at Franklin Pierce University, told the Telegraph the fasted state after waking up is likely the key to the weight loss edge.
“Exercise can burn fat and glucose,” Dr Ma said. “After an overnight fast, the glucose stored in our body is low. Therefore, when we exercise our muscles are likely to burn more fat.
“I would recommend 40 minutes of aerobic exercise before breakfast, such as running or biking.
“Or an evening of brisk walking for the less fit, on a regular basis, for example four to five days a week.”
‘Exciting new research’
People in the morning group also reported having healthier diets and consuming fewer calories per unit of body weight compared with people who exercised later in the day.
According to the findings, people in the morning group also spent a significantly higher amount of time sitting or lying down – not moving – than the others.
But the researchers found that despite this, the lower body mass index and waist size in the morning group persisted.
Clinical psychologist Rebecca Krukowski, professor and co-director of the Community-Based Health Equity centre, University of Virginia, School of Medicine, who was not involved in the study, called it “exciting new research”.
“It is consistent with a common tip for meeting exercise goals – that is, schedule exercise in the morning before emails, phone calls or meetings that might distract you.”
Researchers used data from the 2003-2004 and 2005-2006 cycles of the National Health and Nutrition Examination Survey by the Centres for Disease Control and Prevention in the USA.
A total of 5,285 people were included and split into morning, midday and evening exercisers.
Those in the morning group (642 people) were 10 to 13 years older than the two other groups.
This cluster also had the highest percentage of women, and the majority of them were primarily non-Hispanic white, had a college or higher education, and had never used tobacco or alcohol.
“Our findings propose that the diurnal pattern of moderate to vigorous physical activity could be another important dimension to describe the complexity of human movement,” Dr Ma said.
The findings are published in Obesity, The Obesity Society’s (TOS) journal.