If insufficient sleep can alter hormonal regulation, that has downstream effects on glucose metabolism and blood pressure. Poor insulin sensitivity and high blood pressure might not be dangerous in the short term, but these chronic conditions lead to cardiovascular risk factors such as diabetes, stroke, heart attack, and even death.
When it comes to the brain, we’ve shown sleep loss can change task-related activity involving memory, executive function, and memory. In a more shocking result, science has shown sleep loss can completely alter brain structure. A 2014 study in Neuroreport tested regional gray matter in healthy adults after about 72 hours of total sleep deprivation. Their results found significant loss of gray matter in the thalamus. While overall whole brain gray matter volume remained intact, thalamic regions clearly suffered.
Another study tested chemical levels after 21 days of total sleep deprivation. As it would be unethical to force sleep deprivation in humans for 21 days, this study was conducted on rats. When compared with control groups, sleep-deprived rats showed impaired maintenance of long-term potentiation and balance between antioxidant defenses of the hippocampus.
Probably the most dramatic result from a murine study comes out of the Journal of Neurochemistry. Researchers testes gene transcription in rats deprived of sleep for only a week. Seventy-five different transcripts showed increased expression when compared to controls. These included gene transcripts responsible for coding stress response proteins, immunoglobulins, cortistatin, and more. Sixteen specifically decreased their transcription, such as coding for type I procollagen and dihydrolipoamide acetyltransferase.
In layman’s terms, one week of sleep deprivation altered the genetic ability to code molecules responsible for immune system function, stress management, connective tissue, and metabolism. According to this research, losing sleep can have consequences at the molecular level.
In summary, the common long-term consequences of lack of sleep include:
- Gastrointestinal disorders
- Type 2 diabetes
- Weight gain
- Reduction in thalamic gray matter volume
- Metabolic syndrome
- Reduced antioxidant defense
- Heart disease
- Increased cancer risk
- Potential molecular and genetic changes