Researchers at Carnegie Mellon University and University of Pittsburgh Medical Center have concluded that people who get six hours or less of sleep every night are four times more likely to catch a cold as compared to those who get at least seven or more hours of nap time.

Importance Of Sleep Confirmed: Good Sleep

The Centers for Disease Control and Prevention (CDC) have labeled inadequate sleep a public health epidemic. Poor sleeping patterns lead to road accidents, industrial disasters and medical errors. Scientists have long established the importance of sleep in preventing chronic illnesses, likelihood of disease and premature death.

According to lead author Aric Prather, PhD, Assistant Professor of Psychiatry at UCSF, the study is the first of its kind to associate objective sleep measures with people’s natural sleeping patterns and their risk of getting sick. His previous studies have demonstrated that people who get fewer hours of sleep are prone to illnesses even after being vaccinated. Other studies report that sleep plays a significant role in regulating levels of T-cells (immune cells).

“Short sleep was the most important factor in predicting an individual’s likelihood of catching a cold”, explained Prather. “It made no difference how old the individual was, their level of stress, their race, education or socioeconomic status. Also, it didn’t matter if they were smokers. After taking all these factors into account, statistically, sleep still was the most significant in predicting health”.

The study is entitled ‘Behaviorally assessed sleep and susceptibility to the common cold’ and is published in the journal Sleep.

Study: How Sleep Fights Infection?

Prather collaborated with Carnegie Mellon Psychologist Sheldon Cohen, PhD, who is also the study’s senior author. Cohen has actively investigated social and psychological factors that cause illness. To establish a connection between sleep and infection, Cohen administers volunteers the virus that causes the common cold and observes how different factors influence the body’s ability to fight disease.

For this study, the research team decided to investigate the relation between sleeping habits and susceptibility to cold, using data collected in Prather’s lab. They enrolled 164 participants from Pittsburgh, PA between the years 2007 and 2011. These individuals were subjected to two months of interviews, questionnaires and health screenings to determine a baseline for factors such as stress, alcohol consumption, temperament and smoking. Normal sleeping habits were also recorded a week before administering the virus via nasal drops, and the participants wore sensors that recorded objective measurements of sleep throughout the night.

The volunteers were then sequestered in a hotel and monitored for a week. Daily samples of mucus were collected to determine whether the virus had taken effect.

Stressing On Results: Good Sleep For Good Health

It was seen that the subjects who habitually slept for less than six hours at night were 4.2 times more likely to catch a cold as opposed to those who slept for more than seven hours. Those who slept for less than five hours were 4.5 more likely to develop a cold.

Good sleep, the study undeniably demonstrates the risk of chronic sleep loss in a natural experimental setting based on the participant’s normal sleeping patterns. It highlights the importance of sleep as a public health issue equivalent to exercise and diet.

However, convincing people to adopt healthy sleeping habits is still a struggle. “In today’s busy culture, it is a matter of pride not getting enough sleep and doing a lot of work. We need more studies like this to ascertain that sleep is a crucial part of our well-being”, concluded Prather.