Sleep, diet or physical activity, what's most important for good mental health? Study reveals the key

Researchers suggest that getting good quality sleep, rather than sleep quantity, is the strongest predictor of better mental health and well being in young adults


                            Sleep, diet or physical activity, what's most important for good mental health? Study reveals the key
(Getty Images)

Physical activity, sleep and diet have been associated with mental health and well-being individually in young adults. However, which of these “big three” health behaviors most strongly predict mental health and well-being has been less known. Researchers now suggest that getting good quality sleep, rather than sleep quantity, is the strongest predictor of better mental health and well-being in young adults. 

The findings suggest that future interventions could prioritize sleep quality to maximize mental health and well-being in young adults, suggest authors from the University of Otago, New Zealand.

"This is surprising because sleep recommendations predominantly focus on quantity rather than quality. While we did see that both too little sleep – less than eight hours – and too much sleep – more than 12 hours – were associated with higher depressive symptoms and lower well-being, sleep quality significantly outranked sleep quantity in predicting mental health and well-being. This suggests that sleep quality should be promoted alongside sleep quantity as tools for improving mental health and well-being within young adults,” explains lead author Shay-Ruby Wickham, who completed the study as part of her Master of Science.

The findings

The team surveyed 1,111 young adults (aged 18 to 25 years) from the US and New Zealand. They had to answer an online survey which asked them questions about their sleep quantity and quality; physical activity; and consumption of raw and processed fruit and vegetables, fast food, sweets and soda. The report also looked at demographics, socioeconomic status, body mass index (BMI), alcohol use, smoking, and health conditions.

"While extensive research has shown the mental health and well-being benefits of sleep, physical activity, and diet as individual predictors, research examining all three behaviors together, along with their possible higher-order relationships, is limited. Knowing the importance of each of these lifestyle behaviors, singularly or in combination with each other, and the hierarchical order of importance will inform mental health interventions at both the population and individual level," explains the team.

People in the 18 to 25 age group were asked questions about their sleep quantity and quality, physical activity and consumption of raw and processed fruit and vegetables (Getty Images)

The analysis, published in Frontiers in Psychology, shows that sleep quality could be the most important health behavior predicting mental health and well-being in young adults. Exercise and diet are secondary but still significant factors. More specifically, along with quality sleep, exercising, and eating more raw fruits and vegetables – in that order – were three modifiable behaviors that correlated with better mental health and well-being in young adults.

Depressive symptoms were lowest for young adults who slept 9.7 hours per night, and feelings of well-being were highest for those who slept 8 hours per night. Well-being was highest for young adults who ate 4.8 servings of raw fruit and vegetables per day. Those who ate less than two servings, and also more than eight servings, reported lower feelings of well-being. 

According to the investigators, young adults have been identified as a population at risk of elevated mental health disorders, with extremely high reports of mental health problems and psychological distress. They recommend that health promotion interventions targeting sleep, diet and exercise within young adult populations may help to better mental health and well-being within this at-risk population, “as targeting one individual behavior may not always improve other health behaviors".

“Sleep, physical activity, and a healthy diet can be thought of as three pillars of health, which could contribute to promoting optimal well-being among young adults, a population where the prevalence of mental disorders is high and well-being is suboptimal,” concludes Wickham.

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