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The Importance of Sleep for Optimal Testosterone Production |
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Written by Robbie Durand
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Wednesday, 18 February 2009 |
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Page 3 of 5
Another interesting finding was that the sole predictor of morning testosterone was the workers’ quality of sleep. Having sufficient sleep was more predictive of testosterone levels than age, BMI and smoking. In addition to being sleep deprived from work, many sleep disorders can decrease testosterone levels. Sleep quality is affected by many breathing-related disorders such as sleep apnea, which has been shown to affect approximately four percent of middle-aged men.17
Sleep Apnea Suppresses Testosterone Production!
Sleep apnea happens during sleep when there’s a cessation of airflow that occurs for at least 10 seconds (usually 20 to 30 seconds, but rarely greater than two minutes). Apnea is accompanied by snoring, sleep arousals and hypoxia. The term sleep apnea describes two major sleep-related clinical problems: obstructive sleep apnea and central sleep apnea.
Central apnea is caused by neurochemical stimulation, which can result in impairment of respiratory control of breathing. Obesity is often a factor, but not all patients with central sleep apneas are obese. Approximately 18 to 40 percent of affected patients are no more than 20 percent heavier than their ideal bodyweight.
Obstructive apnea is caused by upper airway obstruction at the level of the pharynx and is the most common form of sleep apnea. What should concern bodybuilders is that a large neck circumference (collar sizes greater than 17.5 inches) has been associated with sleep apnea. Obesity is a major contributing factor to sleep apnea as the excess adipose tissue around the neck collapses the trachea during sleep. Sleep apnea results in a reduction in both LH and testosterone levels. Luboshitzky et al.17 examined healthy young men and compared them to overweight sleep apnea patients and found that sleep apnea resulted in severe testosterone dysfunction. Compared to healthy young men, sleep apnea patients had lower total LH and testosterone levels due to decreased LH pulse amplitude and decreased pulsatile testosterone secretions during the night. When obese patients lose weight, the nightly circadian rhythms of LH and testosterone are restored.19
Obesity in itself suppresses testosterone levels, but the hypoxia that occurs during apnea suppresses testosterone levels as well. Additionally, when apnea patients are placed on nasal continuous positive airway pressure (CPAP) machines (which delivers air into your airway through a specially designed nasal mask), testosterone levels revert back to normal, demonstrating that obesity alone isn’t the sole cause of decreased testosterone levels occurring during sleep.20
When patients with sleep apnea were compared to each other, the degree of testosterone suppression taking place with sleep apnea was directly related to the amount of hypoxia occurring during sleep. Decreased morning testosterone levels, but not LH, is related to the degree of hypoxia.20 For example, Kouchiyama et al.31 found that when sleep apnea patients were compared to each other, the patients who had less severe oxygen saturation had testosterone peaks at 6 a.m., whereas the patients who were classified as having severe oxygen desaturation during sleep exhibited delayed peaks in testosterone for example, at 10 a.m.
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Research and Review 
