Good Mornings And Bad Nights? Happiness Is Higher At Certain Times Of The Day

These feelings, the study shows, can be influenced by the day of the week as well as the season of the year.

Mental health and wellbeing are dynamic. An increasingly large body of research has shown that they can change both across short and longer periods of time. Existing work has shown that mental health and wellbeing can change across a lifetime, while others have examined how they can fluctuate across weeks or months, especially during the recent COVID-19 pandemic.

However, less attention has been paid to whether the same is true across a single day.

In order to address this, researchers explored whether time of day is associated with variations in mental health (depression and/or anxiety symptoms), as well as happiness (hedonic wellbeing), life satisfaction, sense of life being worthwhile (eudemonic wellbeing) and loneliness (social wellbeing). They also wanted to know whether these associations changed across the day, or by season or year.

The team examined data taken from the University College London COVID-19 Social Study, which started in March 2020 and monitored participants until November 2021 and then again up to March 2022.

The aspects investigated in this work were measured by self-reported questionnaires that relied on validated assessment tools, or through direction questions. The latter included things like, “In the past week, how happy did you feel; how satisfied have you been with your life; to what extent have you felt the things you are doing in your life are worthwhile?”

Survey completion was marked with timestamps so the researchers could assess the potential impacts the time of the day had on the respondents. They also contained basic demographic data, including participants’ age, gender, ethnicity, educational attainment, employment status, residential area (whether they lived in a rural or urban location), and whether they had any diagnosed physical or mental health conditions.

In the end, the researchers had complete information for 49,218 people, just over three quarters of whom were women (76.4 percent). Importantly, people educated to degree level or higher were also overrepresented in the sample (68.1 percent), while those of ethnic minority background were very much underrepresented (5.9 percent). The team therefore weighted the sample to reflect these disparities.

The results showed a clear pattern in self-reported mental health and wellbeing across the day, with people generally feeling at their best in the morning. This was the time when they reported lower depression and/or anxiety symptoms, as well as lower loneliness. They also reported the highest levels of happiness, life satisfaction, and worthwhile ratings.

Interestingly, the influence of the day of the week was less clear. It seems people experienced more variation in mental health and wellbeing during the weekends, rather than the weekdays. People also reported higher levels of happiness, life satisfaction, and worthwhile scores on Mondays and Fridays compared to Sundays. Happiness was also higher on Tuesdays.

“For happiness and life satisfaction,” the team write in their paper, “the weekdays showed fewer variations across time compared with weekends. During weekends, both happiness and life satisfaction were at their highest in the morning, decreased sharply until midday, increased steadily into the evening, and then started to decrease again, with the lowest point at midnight.”

In contrast, levels of loneliness stayed consistent across days of the week and times of day.

One factor that did have clear influence on mood, however, was the season. As you can imagine, people tended to report lower levels of wellbeing and happiness during the winter. Mental health was at its highest in the summer across all outcomes, but the seasons did not appear to affect the associations observed across the day.

Despite these interesting results, some caution is needed before broader generalizations are made. Firstly, the data consisted of self-reported information which was given by participants when they chose to fill in the questionnaires. The study has no way of knowing why people chose to respond at different times of day or on different days of the week, which could itself be the result of their mental health and sense of wellbeing at that time.

“In other words,” the team write, “we cannot rule out the possibility of reverse causality, and these associations should not be overinterpreted as causal relationships.”

It is therefore not possible to draw any broader conclusions about causation at this stage.

There was also no evidence available for sleep cycles, geographic latitude, or local weather conditions, which could also influence how people feel.

Regardless, the changes in mental health and wellbeing across the day may be explained by physiological changes related to our body clocks, the authors suggest.

“For example, cortisol peaks shortly after waking and reaches its lowest levels around bedtime. However, it is important to acknowledge the differences between weekends and weekdays.”

“Given there is little evidence that physiological processes differ across different days of the week, differences might be related to other factors that drive [mental health and wellbeing] changes over the course of the day. This could include contextual factors and sequence of daily activities, which are likely to be different between weekends and weekdays.”

Another interesting outcome of this research is the patterns seen in the times of day and mental health and wellbeing across time. It is surprising that they seem to stay consistent across the seasons, which is strange as we would typically assume that the number of daylight hours would affect them.

“Other drivers of the seasonal variation in [mental health and wellbeing] could include weather (temperature, precipitation, humidity) as well as various sociocultural cycles, including cultural holidays, norms and employment patterns,” the team suggest.

Overall the results could have value for informing clinical assessments for patients, especially as the results suggest that people’s mental health is at its lowest at midnight, mid-week, and in winter.

The study is published in BMJ Mental Health.