In a study published in Metabolism in 2006, Dr. George Plante of the Sleep Research Center at the University of Arizona explored the relationship between sleep and vascular disorders. Dr. Plante's study aimed to investigate how variations in sleep patterns and disruptions of the circadian cycle can affect cardiovascular function.
The study first highlighted the well-known fact that cardiovascular diseases such as congestive heart failure and coronary insufficiency can give rise to varying degrees of sleep impairment. However, it also highlighted that certain physiologic events that occur during sleep, as well as long-term unsatisfactory sleep, may cause or increase the risk of cardiovascular conditions such as hypertension, atherosclerosis, stroke, and cardiac arrhythmias.
Dr. Plante's study showed that heart rate abnormalities during sleep in normotensive subjects predict later cardiovascular disease and that their early identification can alert physicians to undertake preventive measures. The study also explored the effect of sympathetic nervous system (SNS) activity on the heart under a variety of experimental conditions, including quiet and paradoxical sleep. The results disclosed significant differences between the responses of spontaneously hypertensive rats and normal rats to SNS stimulation.
The study also examined the impact of disruptions of the circadian cycle on cardiovascular function. There is growing evidence that melatonin, a hormone produced by the pineal gland, can influence important processes such as fluid, nitrogen, and acid-base balance. Dr. Plante's study revealed that human subjects whose nocturnal arterial blood pressure fails to show the "normal" decrement during sleep ("nondippers") are also prone to sleep poorly, exhibit increased SNS activity during sleep, and have an increased risk of total and cardiovascular disease mortality.
Chronic sleep deficit is now known to be a risk factor for obesity and may contribute to the visceral form of obesity that underlies the metabolic syndrome. The rising prevalence of obstructive sleep apnea and central sleep apnea is linked to the modern-day epidemic of obesity. Obstructive sleep apnea is associated with an enhanced risk of having a new stroke or a transient ischemic attack.
In conclusion, Dr. Plante's study highlights the importance of understanding the relationship between sleep and vascular disorders. The study provides evidence of the potential risks and consequences of variations in sleep patterns and disruptions of the circadian cycle on cardiovascular function. It also emphasizes the need for physicians to be aware of the early signs of cardiovascular disease and to take preventive measures to address them.