Beauty Sleep

With changing life styles, more and more individuals are complaining that they need more than 24 hours in a day to accomplish their daily needs - work, play and sleep, in that order! Consequently, sleep bears the brunt of the shortage of time and people end up sleeping less. So, apart from feeling a bit tired does sleeping less really matter?

A report from the University of Pittsburgh examined the relationship between sleep duration and the presence of the metabolic syndrome in 1214 individuals, aged 30 – 54 years, who participated in the University of Pittsburgh’s Adult Health and Behavior (AHAB) registry (Sleep 2008; 31: 635 – 643). There were 4 groups of participants based on sleep duration: < 6 hours (= very short sleepers), 6 – 6.99 hours (= short sleepers), 7 – 8 hours (reference group) and > 8 hours (= long sleepers).  Metabolic syndrome was defined according to the American Heart Association / National Heart Lung and Blood Institute’s (AHA/NHLBI) criteria as the presence of 3 or more of the following: (1) waist circumference > 102 cm in men or > 88 cm in women; (2) fasting serum glucose of ≥ 100 mg / dL or use of oral hypoglycaemic medication; (3) blood pressure of 130 mm Hg systolic, 85 mm Hg diastolic or higher or use of antihypertensive medication; (4) serum triglycerides of ≥ 150 mg /dL or use of hypertriglyceridaemia medication; (5) high-density lipoprotein (HDL) cholesterol of < 40mg / dL in men or < 50 mg / dL in women or use of medication for low HDL cholesterol. Twenty percent of the population was ‘very short sleepers’ and only 8% was ‘long sleepers’. When compared to the reference group, the odds of having the metabolic syndrome in short sleepers and long sleepers were increased between 48 – 83%.

A study from  Korea University looked at 4222 participants in the 2001 Korean National Health and Nutrition Survey and evaluated the relationship between sleep duration and metabolic syndrome [Int J Obes (Lond) 2008; 32: 1091 -1 1097]. The average amount of sleep per night, in hours, was categorized as ≤ 5, 6, 7, 8 and ≥ 9. Those who slept 7 hours per night had the lowest prevalence for metabolic syndrome. Individuals who slept ≤ 5 hours per night had the highest risk for metabolic syndrome, a 74% increased risk. Equally, those who slept ≥ 9 hours per night also exhibited an increased risk for metabolic syndrome. The prevalence of abdominal obesity and hypertension was highest in those who slept ≤ 5 hours per night while the prevalence of hyperglycaemia and hypertriglyceridaemia was highest in those who slept ≥ 9 hours per night.

Researchers from Japan and USA studied the impact of short sleep duration on incident cardiovascular disease (CVD; CVD events include stroke, fatal and non-fatal heart attacks and sudden cardiac deaths) and its possible interaction with nocturnal blood pressure (BP) in 1255 Japanese men and women with a mean age of 70.4 years (Arch Intern Med 2008; 168: 2225 – 2231). Short sleep duration was defined as < 7.5 hours. If the mean night time systolic BP exceeded the day time systolic BP, the individual would be classified as having a riser pattern of BP. Short sleep duration was found to be associated with a 68% increased risk of incident CVD. On comparing individuals with short sleep duration plus a riser pattern of BP to individuals with normal sleep duration plus a non-riser pattern, the risk of incident CVD is increased 4.43 times in those with short sleep duration plus a riser pattern.

Whenever I meet a patient who gives a history of loss of energy and tiredness, I invariably find that they have been burning the candle from both ends – staying awake longer in order to do more! In these cases, you really do not need to see a doctor; what you really need is to listen to your body. Your body is just like a motorcar, abuse it and it will break down quicker, look after it and it will merrily chug along for years.