We constantly encounter bacteria and viruses in our environment, but it is far from every time we get sick. We only become that when our immune system for some reason fails to resist.
"First and foremost, we spend more time indoors and are then more often exposed to bacteria and viruses in the enclosed air," says Mattias Forsell, who researches immunology at the Department of Clinical Microbiology at Umeå University.
- The other reason could be that the body temperature is more often a little lower during the winter, i.e. when we are cold. The body functions optimally at 37 °C and, in theory, immune cells are worse at functioning at lower temperatures. The third reason may be lack of sunlight. The absence of the sun means that there are more viruses in the air. In summer, the virus particles are killed by the sun's ultraviolet light, but in winter the sunlight is weaker. In addition, we get less vitamin D, which is important for the normal functioning of the immune system.
Supporting our immune system therefore becomes especially important during the winter. But is it possible to protect us from infections? No, completely protecting yourself against flu and common cold viruses is basically impossible, says Mattias Forsell.
3 important things to consider for the immune system to function optimally:
1. Sleep properly
- The importance of sleeping well is proven on many levels. Researchers have established that many molecules associated with sleep or wakefulness can influence the activity of the immune system, and vice versa, says Mattias Forsell.
Sleeping at regular times can also help. In a new study, British researchers have concluded that our susceptibility to viral infection is influenced by our internal circadian rhythm. By studying one of the genes that control the rhythm of the biological clock, the researchers discovered that influenza viruses spread more easily towards the evening when the gene is less active. When the researchers disrupted the biological clock gene, in either human cells or mice, they found that the time of infection no longer mattered – viral replication was always high. This suggests that people who work night shifts, or for other reasons have a disturbed circadian rhythm, may be more susceptible to viral diseases.
2. Don't stress
Not stressing and generally "feeling good" provide the best conditions for the immune system. Maybe you've found that being sick makes you feel down, but research suggests that it can also be the other way around.
- For example, we study how serotonin, a signaling substance that controls sleep, appetite, bowel movements and more, affects a certain type of immune cells, says Mattias Forsell. His research group has produced interesting preliminary data.
- It is clear that the immune system and the nervous system continuously talk to each other. Illness and immune activation affect our mood and need for sleep. And changed mental circumstances, such as stress and depression, can thus affect our immune system.
3. Eat healthy and varied
In case of nutritional deficiency, the immune system does not work as it should. Activation of the immune system also requires an extreme amount of energy and countless nutrients are needed.
