TIME spent exercising should not cut into sleep time if people want to get the best health benefits, a new Australian study has found.
The study, by University of Queensland and University of South Australia researchers, found how different exercise schedules could have different effects on health.
It analysed the exercise habits of 129 previously inactive adults aged 18 to 60 years old for six weeks, with three groups exercising for between 150 to 300 extra minutes a week.
The study, UQ research fellow Dr Sjaan Gomersall said, found as people tried to fit in exercise around work, sleep and relaxation time, it could have both positive and negative overall effects.
"When people undertake a new exercise program, the time spent in other domains, such as sleep or screen time, must be reduced to accommodate the new activity," Dr Gomersall said.
"If a new exerciser chooses to reduce screen time to accommodate exercise, for example, then there will presumably be additional health benefits, given that sedentary time is a risk factor for mortality and cardiovascular disease.
"Conversely, if they choose to sleep less, the benefits of physical activity may be reduced and ultimately lead to negative health outcomes such as obesity and depression."
It also found that starting an exercise regime could cut down the time spent watching television by up to 50 minutes a day.
"However, results also showed that this positive health outcome was offset by participants spending an extra 30 minutes a day using computers," Dr Gomersall said.
"This may indicate they were taking work home because they left early to exercise.
"Sleep levels also decreased by around 40 minutes a day during the study, meaning participants lost 20 hours of sleep during the six weeks."