A full day without sleep altered immune cells similarly to the effects of obesity.

Scientists continually emphasize the significance of nighttime rest and the consequences of even brief disruptions in sleep patterns. Recently, researchers warned that individuals sleeping less than six hours a day are at a higher risk for type 2 diabetes compared to those who get seven to eight hours of sleep. Previously, American medical professionals experimentally demonstrated that a single sleepless night can accelerate the onset of Alzheimer's disease symptoms. In another study, doctors concluded that sleep deprivation weakens communication between neurons, comparing this effect to that of alcohol.

A recent article on this subject was published in The Journal of Immunology. In it, specialists from the Dasman Diabetes Institute (Kuwait) aimed to observe how sleep quality affects monocytes—the cells of the immune system. These cells are considered the first line of defense for the body, responding to pathogens and initiating the immune response.

The experiment involved 237 individuals aged 25 to 39 years—112 men and 125 women—who did not suffer from diabetes, hypertension, heart conditions, or other serious illnesses. Participants were divided into three groups based on their body mass index: underweight, overweight, and obese.

Using a wearable device with an accelerometer, ActiGraph GT3X, researchers monitored the participants’ eating habits, physical activity, and sleep patterns for seven days. Additionally, participants provided blood samples to determine the levels of different types of monocytes and inflammation markers. Monocytes are classified into classical, intermediate, and non-classical types. The latter "patrol" blood vessels, responding to signs of damage or pathogens while also participating in regulating the immune response.

Analysis of the collected data revealed that individuals with obesity had the poorest sleep quality: their sleep was fragmented and shorter in duration. Furthermore, compared to the lean participants, this group exhibited elevated levels of non-classical monocytes and markers of chronic non-specific inflammation.

As part of the same study, five lean participants were asked to stay awake for 24 hours. Blood samples were taken from them at the beginning of the experiment, the morning after the sleepless night, and at the end of the trials following two days of recovery with adequate sleep and regular lifestyle.

Doctors found that after a day without sleep, there was a significant increase in the levels of non-classical monocytes in the volunteers, similar to what was observed in individuals with obesity. After the recovery period, the levels returned to normal. However, medical professionals warned that maintaining such shifts could contribute to inflammatory processes in the body and increase the risk of cardiovascular diseases and diabetes.

Researchers plan to continue their work and further investigate the impact of sleep deprivation on immune system cells, as well as examine whether improving sleep quality can mitigate the negative changes in individuals with obesity.