A new study assessed the feasibility of increasing sleep hours in adults with a lack of sleep and analysed the results on nutrient and sugar intake.
The sleep cycle is our most important biorhythm that influences the whole body-mind system. Lack of sleep bothers many people, and the physiology of sleep is still not well understood. The recommended sleep duration is six to nine hours for optimal physical and mental health. However, behavioral sleep curtailment is becoming more common and reports indicate that about 37% of American adults sleep for less than six hours per night. A lack of sleep is a risk factor for many conditions such as obesity and cardio-metabolic diseases. Sleep is now recognized as a modifiable risk factor and interventions to increase sleep duration and quality are being studied to assess the effects of sleep extension on the overall health of sleep-deprived individuals.
Growing evidence points to an association between a lack of sleep and obesity and its related complications. Sleep has been shown to be an important modulator of neuroendocrine function and glucose metabolism. A lack of sleep results in metabolic alterations such as decreased glucose tolerance and alteration of hormones that regulate appetite. In addition, short sleepers usually have poor dietary habits that may impact nutrient intake. Therefore, an effort to increase sleep duration may improve sleep hygiene (the habits necessary to promote good nighttime sleep) and nutrition, as well as help in the maintenance of weight and cardio-metabolic health.
The SLuMBER Study
A new randomized controlled trial published in the American Journal of Nutrition assessed the feasibility of sleep extension using behavioral changes in healthy adults who were sleep deprived. Alongside, the researchers carried out a pilot investigation to study the effect of sleep extension on nutrient intake. The SLuMBER study stands for “sleep lengthening and metabolic health body composition energy balance and cardiovascular risk”.
For the study, researchers recruited 42 normal weight healthy adults with an average sleep duration of between five and seven hours per night. Twenty-one participants from London England were allocated to the sleep extension group and the other 21 to the control group. The participants in the sleep extension group received a 45-minute personalized sleep consultation that aimed to improve their sleep hygiene using evidence-based behavioral changes. The participants selected four sleep hygiene behaviors that were relevant to their lifestyle such as avoiding caffeine before bedtime, not going to bed too full or hungry, or establishing consistent sleep/wake times.
The control group participants received no intervention in their sleeping habits. Measurements for cardio-metabolic markers, BMI, energy expenditure, and body composition were taken at the start of the study and at the end of four-week study period. Following the consultation, the participants kept sleep and food diaries for seven days. Sleep was assessed by wrist actigraphy that measured exactly how long did the participants sleep as well as the time they spent in bed before falling asleep.
Sleep Duration and Quality
The results of the intervention showed that 86% of the participants in the intervention group increased the amount of time spent in bed and about 50% of them increased their sleep duration ranging from 52 minutes to 88 minutes. Interestingly, three participants were able to get their weekly average sleep duration to within the recommended seven to nine hours. However, sleep data from the intervention group suggested that the extended sleep achieved by the participants was of lesser quality than the control group. The researchers indicated that the poor quality of sleep after the intervention may be due to a period of adjustment that is usually associated with a new routine.
The sleep extension intervention resulted in an approximately 10gm reduction in intake of free sugars compared with baseline sugar intake levels of the participants. The study results also showed trends indicating a reduced intake of carbohydrate and fat in the intervention group compared to the control group. The researchers found no significant difference in body weight, body composition, waist circumference, total energy intake, cardio-metabolic risk, and physical activity between the sleep extension and control group.
Sleep Well and Stay Healthy
Sleeping well may not guarantee good health but it clearly proves to be vital for maintaining overall mind and body functions. The present study shows that a lack of sleep may lead to unhealthy nutritional intake. Extending sleep resulted in reduced free sugar intake. In other words, getting enough sleep means lesser consumption of sugars in syrups, fruit juices, honey, and sugars added by manufacturers in various food products. The results highlight that small and simple changes in sleep habits may help people consume healthier diets.
This study is the only randomized controlled trial so far to investigate sleep extension using behavioral interventions in free-living conditions. There are, however, some limitations. The allocation of the participants was not blinded, the sample was predominantly comprised of white women, there is a possibility of reporting bias due to use of self-reported dietary records, and a short intervention period of four weeks were some of the important limitations.
It is complicated to determine the risks associated with lack of sleep. However, healthy sleeping habits not only make people feel better, they also increase the chances of living a healthier life. This study provides evidence to conclude that personalized sleep extension interventions that target behavioral changes for better sleep hygiene may help in longer sleep durations for sleep-deprived people.
In addition, results also suggest that an increased time in bed before falling asleep may lead to lower sugar consumption and healthier food choices. This study provides evidence that a lack of sleep may be a modifiable risk factor for obesity, and that interventions to increase sleep duration may an effective tool for decreasing sugar intake. The authors express the need to further investigate the association between lack of sleep and nutrient intake in more detail.
Written by Preeti Paul, MS Biochemistry
Reference: Haya K Al Khatib etal., Sleep extension is a feasible lifestyle intervention in free-living adults who are habitually short-sleepers: a potential strategy for decreasing intake of free sugars? A randomized controlled pilot study. Am J Clin Nutr 2018;107:43-53