Exercise and sleep

Regular exercise has been shown to improve sleep quality. This article discusses that research in the past decade has confirmed that. However, I'm unsure of some of the statements in this article. Specifically, how taking sleeping pills is as dangerous as smoking a pack of cigarettes per day. No studies are cited, which makes it difficult to assess the accuracy of such statements.

Obstructive sleep apnea and exercise capacity

This study is a cross-sectional evaluation of the relationship between obstructive sleep apnea (OSA) and exercise capacity. According to the authors, how OSA affects exercise capacity is not clear, as prior studies have conflicting results. In this study, researchers did sleep studies on participants and put them into two groups. Those with no or mild OSA, and those with moderate or severe OSA. They then measured their exercise capacity and compared the results. The main finding was that OSA was associated with decreased exercise capacity. And more severe OSA was associated with worsening exercise capacity. The mechanism behind why OSA would affect exercise capacity is not clear. The authors speculate that it could be due to changes in energy pathways, changes in muscle fiber structure, and/or changes in blood vessels in muscles - thought to be a result of low oxygen levels associated with OSA.

Eexercise and sleep

Exercise has been shown to improve sleep quality. This study was looked at the relationship between physical activity and subjective and objective sleep in midlife women. Physical activity was assessed with questionnaires and the level of activity was split into 3 domains. The first domain was labeled Active / Living and consisted of things like watching television and active transportation such as walking to work. The second domain was Household / Care-giving activities such as housework and child care. The last domain was Sports / Exercise which included participation in recreational activity or sports. The women's sleep was measured via in-home sleep study, daily sleep diaries, and questionnaires about their sleep.

The results showed that women who consistently participated in regular Sports / Exercise had better objective and subjective measurements of sleep, including sleep quality, sleep continuity, and depth, but not sleep duration. Women in this group also had reduced odds of meeting the diagnostic criteria for insomnia. This relationship was observed despite statistical adjustment for factors such as body mass index and other health behaviors. This association was not seen for those women in the domains of Active / Living and Household / Care-giving.

The relationship between the Sports / Exercise group and sleep was strongest when the pattern of activity existed over multiple years rather than just exercising immediately prior to the sleep assessment. In other words, regular exercise over many years may improve sleep more than sporadic exercise.

Exercise and insomnia

I was taught that regular exercise can improve sleep quality. My patients have told me that sometimes they sleep better if they are "worn out" from exercise or just physical exertion. Exercising upon awakening can help regulate your body clock, giving it a routine. This study in the Journal of Clinical Sleep Medicine studied 11 women with an average age of 61 years. They had the women wear actigraphs, which measure sleep at home. The women also did moderate aerobic exercise 3-4 times per week. The results showed that exercise duration did not correlate with sleep improvements. But sleep duration did correlate with exercise duration - the shorter the total sleep time, the shorter the exercise duration the next day. This makes sense to me. From my own experience, if I get little sleep while on call, I am less likely to exercise the next morning.

Obstructive sleep apnea may reduce exercise capacity

This article discusses research showing a link between obstructive sleep apnea (OSA) and decreased exercise capacity. Specifically, the results showed that severe OSA was associated with reduced functional aerobic capacity, impaired heart rate recovery after exercise, and higher resting, peak, and post-exercise blood pressure. The study did not determine if treating the OSA improved exercise capacity.

Exercise and diet can prevent obstructive sleep apnea from worsening.

Here is a study about obstructive sleep apnea (OSA), exercise, and diet. As you may know, OSA is associated with obesity. Weight loss can reduce the severity, and weight gain can worsen OSA over time. This study is out of Finland. Researchers followed 81 adults with mild OSA and had some follow a diet and exercise program for one year. The others did not. After 4 more years, researchers checked their weight and OSA level. Those that did the diet and exercise program lost an average of 12 pounds. Six had OSA that progressed to moderate, but none were severe. The other group gained one pound on average over the 4 years. 12 worsened to moderate OSA and two had severe OSA.

The researchers concluded that weight loss may lessen the chance of OSA worsening. This is good, as the more severe the OSA, the higher the risk of cardiovascular consequences.

Exercising close to bedtime may not disturb sleep

This article discusses results of a National Sleep Foundation poll showing that exercise close to bedtime does not interfere with sleep. The article discusses that it is not true that exercise close to bedtime will disrupt sleep. I completely agree. I used to be a long distance runner. In high school and high school, I would run late at night after work. I slept like a baby. But the article misses the important point about exercise and insomnia. For those with chronic insomnia, exercise close to bedtime can worsen insomnia.

This article could be about anything you hear about sleep - don't drink caffeine before bedtime, watch TV in bed, sleep in on the weekends, take naps. All of these are fine to do...IF you don't have insomnia. If you do have insomnia, than the above activities can worsen the insomnia. So in you "good" sleepers, go ahead and workout close to bedtime. For you chronic insomniacs, you also need to exercise, but do it in the morning, or no later than late afternoon.

Non-drug treatment of restless legs syndrome

Restless legs syndrome (RLS) is an uncomfortable sensation in the legs that occurs at rest, more often in the evening, and is relieved temporarily with movement. We don't know what causes RLS, but researchers think it may have something to do with dopamine dysregulation. RLS is often treated with prescription medications. However, sometimes non-medicine treatments can help. This article reviews some of the evidence supporting those non-drug treatments.

Regular exercise has been shown to relieve RLS. Proposed mechanism is an increase in circulation, release of endorphins, and increase in dopamine. More recently, pneumatic compression stockings have shown to be helpful. These are air filled wraps worn around the legs - they repetitively fill and empty the air resulting in a massaging action and can improve circulation. If you don't have a pair of pneumatic compression stockings laying around, regular massage has been shown to be helpful, perhaps by increasing circulation, a counter stimulation action, or generation dopamine. Near-infrared light has been shown to be helpful, possibly by increasing circulation. Acupuncture has not been shown to be effective for RLS when compared to no treatment. Certain vitamins and minerals have been shown to be helpful - vitamin E, vitamin B12, multivitamins with vitamin C, glucosamine, zinc, folic acid, vitamin D, and magnesium made the list.

RLS has been associated with low iron, and sometimes I use iron therapy to help with the symptoms. This often takes months of daily iron intake to increase the levels. I don't recommend people taking iron though unless the level is low, as too much iron is not healthy.

Exercise, Diabetes, Sleep Apnea, and Death

I saw a report about a study presented at the annual meeting of the Endocrine Society. The study involved male veterans with diabetes and obstructive sleep apnea (OSA). Apparently, good exercise capacity is associated with a lower mortality risk in patients with type 2 diabetes. Also, studies have shown that patients with OSA have an increased mortality risk compared with those without OSA.

In this study, researchers measured the fitness levels of 567 male veterans averaging 62 years old. After taking other risk factors into account, like race, smoking, and medication use, the study results showed that men with low fitness levels had a 75% higher risk of death than those with high fitness levels. The change in death risk was proportional to the fitness level too.

This study is important because diabetes and OSA are both increasing in prevalence, probably a result of the increasing obesity rates. And as weight goes up, fitness levels generally go down. One thing I don't know is if the patients with OSA were being treated with CPAP, which might help lower their death risk, regardless of fitness level.

Exercise and Insomnia

People with chronic insomnia do not necessarily respond to a single treatment type. In an article in the June 2010 edition of the Journal of Clinical Sleep Medicine, the authors studied the effect of exercise on chronic insomniacs that were healthy otherwise and did not exercise regularly. They found that moderate intensity aerobic exercise decreased anxiety and improved sleep quality, when studied in the sleep lab and when they asked the participants. There was no significant improvement in anxiety or sleep quality with high intensity aerobic exercise or moderate intensity resistance exercise (weight training).

Before you go out and hit the running trail, some caution is advised. This study was small and only measured participants' response after one session of exercise. Also, the moderate intensity aerobic exercise group had the most severe insomnia to begin with - and therefore had the most to gain with the exercise session.

Exercise can be an important part of healthy sleep. Exercise too close to bedtime can disrupt sleep, especially in the beginning of the night. You might struggle more if you go for a run at 10 pm, then grab a shower, and hit the sheets by 11 pm. You'll probably need more wind-down time - perhaps 4-6 hours after exercise, before trying to sleep.