Obese people trying to improve their health are better off exercising in the evening, scientists claim. An eight year study from the UK Biobank revealed that physical activity between 6pm and midnight was linked to greater health benefits for obese people.
Researchers from the University of Sydney followed 30,000 people for the study, published in the journal Diabetes Care. Using fitness trackers they found that those who did the majority of their moderate to vigorous physical activity in the evening had the lowest risk of premature death and death from cardiovascular disease.
Short bouts of three minute activity that left them slightly out of breath also appeared to be more important than their total amount of physical activity daily. Dr Angelo Sabag, Lecturer in Exercise Physiology at the University of Sydney’s Charles Perkins Centre said: “Exercise is by no means the only solution to the obesity crisis, but this research does suggest that people who can plan their activity into certain times of the day may best offset some of these health risks.
“Due to a number of complex societal factors, around two in three Australians have excess weight or obesity which puts them at a much greater risk of major cardiovascular conditions such as heart attacks and stroke, and premature death."
The authors say their findings are 'significant' due to the large scale of the study and by defining exercise as anything strenuous for three minutes or more. Joint first author Dr Matthew Ahmadi National Heart Foundation postdoctoral research fellow at the University, said: "We didn’t discriminate on the kind of activity we tracked, it could be anything from power walking to climbing the stairs, but could also include structured exercise such as running, occupational labour or even vigorously cleaning the house.”
The researchers used data from UK Biobank and included 29,836 adults aged over 40 living with obesity, of whom 2,995 participants were also diagnosed with Type 2 diabetes. Participants were categorised into morning, afternoon of evening based on when they undertook the majority of their aerobic exercise as measured by a wrist accelerometer worn continuously for 24 hours a day over seven days at study onset.
The team then linked health data from the NHS to follow participants' health trajectory for 7.9 years. Over this period they recorded 1,425 deaths, 3,980 cardiovascular events and 2,162 microvascular disfunction events.
To limit bias, the researchers accounted for differences such as age, sex, smoking, alcohol intake, fruit and vegetable consumption, sedentary time, education, medication use and sleep duration. They also excluded participants with pre-existing cardiovascular disease and cancer.
Professor Emmanuel Stamatakis, Director of the Mackenzie Wearables Research Hub at the Charles Perkins Centre and senior author on the paper, said: “It is a really exciting time for researchers in this field and practitioners alike, as wearable device-captured data allow us to examine physical activity patterns at a very high resolution and accurately translate findings into advice that could play an important role in health care.
"While we need to do further research to establish causal links, this study suggests that the timing of physical activity could be an important part of the recommendations for future obesity and Type 2 diabetes management, and preventive healthcare in general.”
