Can’t stick to a diet and exercise routine? Get to bed earlier, scientists say

Getting at least seven hours of sleep every night will help with you stick to a weight-loss and exercise routine, a study shows.

Researchers at the University of Pittsburgh signed up 125 middle-aged adults, mostly women, who were overweight or obese to a year-long fitness program.

Participants were tasked with following a calorie-restricted diet and upping their daily exercise.

Although adherence to the plan dwindled in both groups over time, scientists found that those who were better slept were more likely to eat less and exercise more.

The Centers for Disease Control and Prevention (CDC) says that all adults should get at least seven hours of sleep every night.

But estimates suggest that as much as one in three consistently fails to hit this level.

Getting just three nights of too little sleep triggers a dip in mental and physical health, causing a decline in concentration, mood and even breathing problems.

There is even evidence that not hitting seven hours a night makes someone more likely to overeat and crave fatty, salty and sugary snacks over whole foods.

In the study, nine in ten participants were female and all had a BMI between 27 and 44 — putting them in the overweight and obese categories.

All participants were signed up for a weight loss program and had data on their sleep and adherence to the program taken at the start, at month six and month 12.

Adherence to the weight loss program was measured by percentage of group intervention sessions attended; percentage of days in which each participant ate between 85-115 percent of their recommended daily calories; and change in daily duration of moderate or vigorous physical activity.

Sleep was scored from zero to six, with six being the highest score, based on the below sleep factors.

These were: Consistency, satisfaction, alertness, timing, efficiency (time in bed while actually asleep) and duration.

Each factor was scored one for ‘good’ or zero for ‘poor’.

Sleep was scored using patient questionnaires, a sleep diary and seven-day readings from a wrist-worn device that recorded sleep, waking activity and rest.

Participants had their caloric intake tracked by entering their consumption into a mobile phone app, and physical activity was measured using an accelerometer worn on the wrist. These measurements were also taken at the start of the plan and at six months and 12 months into the plan.

Results were then analyzed comparing participants that had and had not got adequate sleep.

During the study period, 79 percent of participants attended group sessions for the first six months, but over the next six-month period this fell to 62 percent.

Caloric goals were met on 36 percent of days in the first six months, but then 21 percent over the next six. 

And total moderate-to-vigorous daily activity time rose 8.7 minutes over the first six months, but then decreased by 3.7minutes over the second six months.

Analysis showed that participants who were getting enough sleep were more likely to stick to the plan.

They were also more likely to keep attending group sessions, adhere to the diet and hit their physical activity goals.

No data on the amount of weight lost by either group was provided by the researchers.

There was also no information given on what fitness plan they were following. 

Dr Christopher Kline, an expert in sleep at the University of Pittsburgh, Pennsylvania, said: ‘Focusing on obtaining good sleep — seven to nine hours at night with a regular wake time along with waking refreshed and being alert throughout the day — may be an important behavior that helps people stick with their physical activity and diet modification goals.

‘A previous study of ours reported that better sleep health was associated with a significantly greater loss of body weight and fat among participants in a year-long, behavioral weight loss program.’

He added: ‘We had hypothesized that sleep would be associated with lifestyle modification; however, we didn’t expect to see an association between sleep health and all three of our measures of lifestyle modification.

‘Although we did not intervene on sleep health in this study, these results suggest that optimizing sleep may lead to better lifestyle modification adherence.’

The study will be presented today at the American Heart Association’s Epidemiology, Prevention, Lifestyle and Cardiometabolic Health Scientific Sessions 2023 being held in Boston, Massachusetts.