Wellness & Fitness

Catching up on ‘lost’ sleep does not reduce disease risk

sleep

People often sleep more on weekends than they do during the week. FILE PHOTO | NMG

Due to long working hours and hectic weekday schedules, most working Kenyans often look forward to weekends when they can sleep longer to compensate for lost sleep time.

This serves as a consolation to most people who believe that the many hours of sleep on Saturday and Sunday enable them to reap sleep benefits lost during the week.

Martin Mburu, a Nairobi-based accountant, states that he always feels fresh and energetic on Mondays after having slept well over the weekend.

"I work in a very busy audit firm. We serve many clients and the earliest I can leave the office is around 10 at night. So on average, I sleep for about four hours— from midnight to four in the morning when I begin preparing for work."

According to the World Health Organisation (WHO), adults should sleep for about seven to eight hours daily so as to enjoy maximum sleep benefits.

Going by this target, Martin only gets 50 percent of sleep time from Monday to Friday.

But unknown to him, just as many Kenyans, the compensatory long hours of sleep over the weekend does not help much.

A new study published in the current Biology Journal shows that extra sleep on weekends does not reduce metabolic problems caused by insufficient sleep.

Metabolism is the process the body uses to get or make energy from the food (carbohydrates, proteins or fats) consumed.

Enzymes or chemicals in the digestive system break the food parts down into sugars and acids that act as fuel for the body, hence enabling it to function optimally.

A metabolic disorder or problem occurs when abnormal chemical reactions in the body — such as those caused by daily insufficient sleep — disrupt this process.

This causes the body to have either too much or too little of the essential substances needed to stay healthy and alive. Ultimately, the metabolic problems impede the proper functioning of body organs.

The researchers noted that the new study adds to evidence that insufficient sleep is a risk factor for metabolic disorders.

Chronic sleep loss

It also shows that catching-up on sleep over the weekend is not the solution to chronic sleep loss during the week.

"The key take-home message from this study is that weekend recovery or catch-up sleep does not appear to be an effective counter measure strategy to reverse sleep loss induced disruptions of metabolism," said Kenneth Wright, lead author of the study from the University of Colorado Boulder.

He noted that people often sleep more on weekends than they do during the week. Yet, for a long time, the advantages or disadvantages of such sleep patterns on people’s metabolic health was unclear.

With the aim of getting an answer to this puzzle, the researchers enlisted healthy young adults during the study period.

Each participant was randomly assigned to a particular group. The first category had plenty of time to sleep. They slept for nine hours each night for nine days.

The second group had five hours of sleep daily over the same period.

Those on the third group slept for five hours for five days. They then proceeded to sleep as much as they liked during the weekend before returning to another two days of restricted sleep.

Weight gain

In the two sleep restricted categories (second and third group), insufficient sleep led to an increase in snacking after dinner and weight gain.

During the weekend recovery sleep in the third group, study participants slept an hour longer on average than they usually would.

On these days, they also consumed fewer extra calories after dinner than those who got insufficient sleep.

However, when they went back to getting insufficient sleep after the weekend, they ate more after dinner as their weight continued to rise.

The sleep restriction in the second group of participants was also associated with a decrease in insulin sensitivity of about 13 percent.

But the group that had a chance to sleep more on the weekend fared worse.

The insulin sensitivity of their whole body, liver, and muscle decreased by 9 to 27 percent after they got insufficient sleep again, once the weekend was over.

"Our findings show that muscle and liver specific insulin sensitivity were worse in subjects who had weekend recovery sleep. These metabolic aberrations weren't seen in the people who got less sleep all along," stated Christopher Depner, another lead author of the study.