Orexin, also called hypocretin, is a neurotransmitter that regulates arousal, wakefulness, and appetite. Scientists suspect that narcolepsy is caused by a lack of orexin in the brain due to the destruction of the cells that produce it. Read on to learn about this neurotransmitter and factors that may naturally increase it. What Is Orexin and Why Is It Important?
The brain contains about 10,000 to 20,000 neurons in the hypothalamus , but axons from these neurons extend throughout the entire brain and spinal cord, where there are also receptors for orexin.
Science suggests that brain orexin/hypocretin neurons stimulate wakefulness , alertness , eating, reward-seeking, and healthy glucose balance [ 1 ]. What Does it Do?
Orexin is not just any molecule in our body. Some scientists say that whenever we’re tired or fatigued, orexin is suppressed [ 2 ].
It’s not like orexin is one of the many systems that stimulate wakefulness. It’s considered to be by far the most significant stimulator of wakefulness. Histamine is also involved, but orexin activates the histamine system [ 2 ].
Researchers suspect that there are many hormones and other systems in the body that interact with orexin.
Therefore, the orexin system seems to be central to productive human functioning and good mood. However, orexin’s role is a relatively recent discovery. Larger human studies are needed to better understand its effects on health [ 2 ]. Narcolepsy
There are two main types of narcolepsy: type 1 and type 2. Measuring orexin levels helps diagnose type 1 narcolepsy [ 3 ].
Doctors need the following to diagnose type 1 narcolepsy [ 4 ]: Hypersomnia (extreme sleepiness)
Cataplexy (episodes of muscle weakness in response to emotional stimuli), and/or
Orexin (hypocretin-1) concentrations in the CSF (cerebrospinal fluid) of 110 pg/mL or less
The exact cause of narcolepsy is still unknown. Unproven, experimental theories suggest that narcolepsy may result from immune imbalance, specifically an elevated Th2 immune system, in some people. Another study found elevated TNF and IL-6 [ 5 , 6 ].
Limited research suggests that orexin also increases metabolism and body temperature. According to this theory, people that feel cold and tired may, among other factors, have low orexin [ 7 ].
Orexin also seems to increase hunger via increased neuropeptide Y expression in the arcuate nucleus of the hypothalamus [ 8 ].
Animal models suggest that low levels of orexin cause obesity , even when fewer calories are consumed. This hasn’t been confirmed in humans [ 9 ].
One hypothesis posits that orexin is a significant factor in why consuming sugar makes people fat. They claim that this is because people feel tired after eating sugar, since it causes blood sugar levels to spike and orexin to fall. So, instead of burning calories, people go to sleep . Although plausible, this hypothesis has yet to be tested [ 9 ].
Another team of researchers claimed that higher levels of orexin-A cause people to be happier. They’re still lacking solid data, though, since this theory is mainly based off the fact that the incidence of depression is higher in narcolepsy.
Yet another stream of research found that orexin and its receptors may decline with age. Plus, orexin may cause people to increase oxygen use because it might increase metabolism. Future research has yet to clarify and solidify all these findings [ 9 , 10 ]. Factors that May Increase Orexin
If your goal is to increase orexin to improve your fatigue – or extreme exhaustion-related issues – including those of chronic fatigue or depression – it’s important to talk to your doctor, especially low energy levels are significantly impacting your daily life.
Your doctor should diagnose and treat any underlying conditions causing your symptoms.
Remember that the existing evidence does not suggest that low orexin causes fatigue or mood disorders.
There’s also no precise way to measure orexin levels outside of research studies and diagnosing type 1 narcolepsy. For narcolepsy, a healthcare professional has to take a person’s cerebrospinal fluid, which is an invasive procedure reserved only for specific cases.
Complex disorders like chronic fatigue syndrome always involve multiple possible factors – including brain chemistry, environment, health status, and genetics – that may vary from one person to another.
Additionally, changes in nerve tone and brain chemistry are not something that people can change on their own with the approaches listed here. Instead, the factors mentioned in this article are meant to improve energy levels and support overall mental health and well-being. Most are backed up only by limited human or animal studies.
Therefore , you may try the strategies listed below if you and your doctor determine that they could be appropriate . Read through the approaches we bring up and discuss them with your doctor before trying them out. This is particularly important if you plan to take any dietary supplements.
Supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective.Finally, have in mind that none of these strategies should ever be done in place of what your doctor recommends or prescribes. 1) Resolving Chronic Inflammation Research suggests a link between orexin and chronic inflammation. Persistent, low-grade inflammation also seems to be tightly tied to fatigue and low cellular energy, according to recent scientific findings [ 11 , 12 ].Elevated inflammation from cytokines like IL-1b and TNF is hypothesized to cause fatigue by the suppression of orexin neurons [ 13 , 14 , 15 , 16 ].Just before the normal time of sleep onset for rats, TNF levels in brain tissue were shown to be 10-fold higher than their daily minimum. This hasn’t been verified in humans, though [ 17 ].If you are experiencing chronic inflammation, work with your doctor to resolve the underlying issue causing your symptoms. 2) Exercise Getting regular, moderate exercise is good for overall health. We know from experience that it makes us feel energized, and some scientists think orexin might be one of the reasons.Limited human […]