Science Update

New review demonstrates the impact of sleep duration and metabolic syndrome

Metabolic syndrome is a significant health care problem in the United States, yet it is preventable and reversible through lifestyle changes, proper nutrition and supplementation, exercise and stress management.

In a review published last month in Nutrients, researchers investigated the association between sleep duration and metabolic syndrome in the 2013/2014 National Health and Nutritional Examination Survey (NHANES).

Sleep disruption is commonly associated with type 2 diabetes and obesity due to the effect of dysglycemia. This altered glucose metabolism is associated with not only poor sleep but also shorter sleep duration and an increased risk of sleep apnea.

This new review was a cross-sectional study including 2,737 individuals. Assessment models analyzed the relationship between metabolic syndrome disease severity and sleep duration. As a result, the lowest average disease severity score was associated in individuals sleeping 7 hours per night. Shorter and longer sleep durations were associated with a higher disease severity as well as a higher risk of metabolic syndrome.

There are some possible mechanisms involved. Growth hormone release takes place during stage 3 in sleep. This is considered the most important stage of sleep as numerous activities such as fat burning and general regeneration and repair take place during this time. In addition, the longest part of stage 3 occurs prior to midnight. Therefore, individuals going to sleep later would suppress growth hormone. Furthermore, advanced glycation end products (AGEs) are significantly higher in individuals with chronic sleep disturbance. This increases inflammation and sympathetic nervous system activity.

Previous research has also shown how sleep disruption can increase amyloid beta and tau proteins. It is highly unlikely that there is an overall increased risk of developing cognitive decline simply from a few nights or even a week of poor sleep.  Amyloid beta and tau protein levels will go back down after the next good night’s sleep; however, the main issue is with those who have chronic sleep issues. This can lead to chronically elevated amyloid levels which in turn lead to an increased risk of cognitive decline.

In order to help promote restful sleep it is important to address an individual’s bedtime habits and environment. Limiting the use of screens at bedtime is crucial, although very difficult for many in today’s society. If necessary, apps such as Night Shift for smartphones and f.lux for laptops can be helpful. Blue light blocking glasses may also be beneficial. In addition, it is important for people to establish a sleep pattern, going to bed around the same time every night. When the timing of sleep is shifted, even if the duration of sleep is the same, it is not going to be as restorative. Caffeine and other stimulants can interfere with sleep and should be avoided four to six hours before bedtime. Finally, workouts are best done earlier in the day, as exercise increases cortisol and can make falling asleep difficult. If early workouts are not possible, consider phosphatidylserine post-workout. Other nutrients to consider to help restore sleep include magnesium l-threonate, valerian root, passionflower, lemon balm, melatonin, and phytocannabinoids.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Smiley A, King D, Bidulescu A. The Association between Sleep Duration and Metabolic Syndrome: The NHANES 2013/2014. Nutrients. 2019 Oct 26; 11(11).