Power cuts and sleep: Students link load shedding to anxiety, disrupted rest and lower grades

South Africa endured its worst year of load shedding (scheduled power cuts by the country’s utility, Eskom) in 2023. The power went off on 335 of the year’s 365 days, often several times a day. Since then, the country has gone more than a year and a half without these planned power cuts.

Much has been written about how load shedding affected businesses, health care and the economy. But far less is known about the effect on people’s sleep.

As sleep scientists and members of the South African Society for Sleep and Health (SASSH), we are interested in studying, and raising awareness about, the importance of sleep to people’s well-being.

People usually sleep within a specific window of time, and if their sleep is interrupted, they get less sleep. Fragmented sleep and short sleep duration have been associated with poor health and cognitive outcomes, including higher cardiometabolic risk (diabetes, high blood pressure and heart problems), lower cognitive performance (attention, executive function and learning), higher risk of developing depression or anxiety and chronic pain.

Sleep is easily disturbed by the world around us, including light, noise, temperature and worry. Load shedding changes all of these at once. We wanted to gain insight into how load shedding affected the sleep of university students in particular. This seemed an important group to study, as they already tend to sleep poorly, keep irregular hours and carry heavy workloads. Any extra disruption could, therefore, have an impact on both their health and their studies.

Between August and November 2023, more than 1,100 students at the University of the Witwatersrand in Johannesburg completed our anonymous online survey. We asked how load shedding affected their sleep, whether they had access to backup power and how outages affected their studying and grades. Specifically, we wanted to understand how access to alternative power sources might make a difference to sleep.

Load shedding has eased, but South Africa’s grid remains under pressure. Our study raises important considerations for universities, not only in South Africa but in any country that faces unreliable electricity generation and distribution.

What we found

Nearly three in four students considered their sleep affected by load shedding. Of those, four in five said it made their sleep worse. The most common complaint was broken sleep, with students waking more often during the night.

The reasons students gave were revealing.

Almost half lay awake worrying about appliances such as refrigerators, phones and internet routers not being powered, and about keeping food fresh or having an internet connection. Nearly a third were anxious about security in the dark. A similar number found their bedrooms too hot or too cold, as they couldn’t power fans or heaters. About a third said they took longer to fall asleep because of disrupted daily and sleep routines, as well as increased generator noise.

Timing mattered. Students reported that outages between 8 p.m. and 12:30 a.m. were the most disruptive. This period covered the evening routine of cooking, washing and studying, and included these students’ average bedtime of 11 p.m., which they reported in our study.

Not everyone slept worse. About one in five affected students said they slept better. Most of them said this was because screens and Wi-Fi were switched off and their rooms became darker and quieter.

Backup power lessens those effects, but not equally

Backup power made a difference, but not all backup power was equal. Students with an alternative supply had roughly 60% lower odds of reporting worse sleep, after we accounted for factors such as age, sex and where they lived.

About half of the participants lived in family or private housing, away from the university. The other half lived in university residences or dormitories. At the time, the university had a generator fleet that partially powered on-campus residences.

Among those with backup power, generator and battery inverter users reported worse sleep about half the time. Among solar users, it was fewer than one in four. Generators are loud and cycle on and off, which can interrupt sleep. Access to backup power was also uneven. Only 40% of participants had access, with those living in university residences having greater access than those living at home.

Sleep and studying

Poor sleep and poor studying went together. Two-thirds of students said load shedding had affected their studies, and more than half of these reported a drop in grades. Students who slept worse were more likely to report lower grades and to arrive late for class.

More than four in 10 said they simply studied less during outages.

Sleep plays a central role in learning. Sleep helps the brain store what was learned during the day and remove unnecessary memories “to start afresh” the next day.

Our study cannot prove that load shedding caused grades to fall, but the pattern fits what sleep research already shows.

Why it matters

Our study offers some of the first evidence on how planned power cuts affected sleep in young people.

Planned outages are still part of daily life across sub-Saharan Africa and in countries such as Nigeria, Ghana, Zambia and Pakistan.

The findings raise practical considerations for universities, energy planners and households. They suggest that quieter backup options such as solar may protect sleep better than generators.

They also suggest that late-evening outage slots carry a particular cost.

For students, keeping a regular sleep routine during outages may help, rather than filling the dark with phone screens. The lights may come back on, but sleep lost while they are off is harder to recover.

Who’s behind this story?

Swati Mestri

Swati Mestri holds a bachelor’s degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space.

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Andrew Zinin

Master’s in physics with research experience. Long-time science news enthusiast. Plays key role in Science X’s editorial success.

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This article is republished from The Conversation under a Creative Commons license. Read the original article.