Scientists Pinpoint When the Afternoon Slump Strikes — and How to Fight It

Scientists say the familiar afternoon energy crash is a predictable biological effect that most people experience in the early afternoon, with a sharp dip in productivity typically occurring around 1:30 p.m. and a secondary lull shortly after.

Researchers and sleep scientists describe the slump as the result of two competing forces: the circadian system that promotes alertness at certain times of day and the increasing "sleep pressure" that builds the longer a person is awake. In a survey and timing analysis of office workers, the largest concentration of peak productivity was reported at about 10 a.m., while just under 60% of respondents reported a dip in performance roughly at 1:30 p.m. A separate study of about 2,000 employees placed the mean time of the first midafternoon slump at 1:27 p.m., followed by another drop at 2:06 p.m.

Neuroscientists say the afternoon decline in alertness is not solely the product of workplace factors such as meetings, screens or interruptions, although those contribute. Dr. Ravia Allada, a neuroscientist at the University of Michigan, has described the situation as a literal ‘‘fight’’ between the circadian drive for wakefulness and mounting sleep pressure; when sleep pressure wins, people feel sluggish.

Lifestyle factors modulate how pronounced the slump becomes. Irregular bedtimes, poor sleep quality and dietary choices can intensify daytime tiredness. Nutrition researchers note that meals high in refined carbohydrates and added sugars—white bread, pasta, sugary cereals and pastries—are rapidly digested, produce a sharp blood-sugar spike and prompt an insulin response that often leaves people feeling lethargic after an initial boost. Professor Sai Krupa Das, an expert in metabolism at Tufts University, recommends substituting sugary breakfast items with slower‑releasing options such as porridge or plain yoghurt topped with berries and seeds; fibre, protein and antioxidants can sustain energy and support focus through the afternoon.

Practical measures tested in workplace surveys and clinical studies can reduce the impact of the afternoon dip. Short, timed naps of about 20 minutes are associated with reduced sleep pressure and improved performance when a longer rest period is unavailable. Physical activity—especially briefly breaking up long periods of sitting with short walks—has been shown to raise alertness and increase daily energy expenditure. In one workplace poll, 25% of employees reported that a walk outside boosted their midafternoon energy. An Italian physiology study led by Francesco Luciano found that interrupting sedentary time with brief strolls meaningfully increased daily energy expenditure and could improve overall health.

Workplace factors remain relevant. In a OnePoll survey tied to the timing research, more than a quarter of respondents blamed extended screen time for their dip in productivity, 22% cited insufficient breaks away from their desk, nearly a quarter blamed frequent interruptions, 31% said coffee gave them an midday lift and almost half reported that being around colleagues improved their productivity.

Experts caution that while the afternoon slump is normal for most people, excessive daytime sleepiness that persists after improving sleep routines, diet and activity can indicate an underlying medical condition. Dr. Derk Avidan and other sleep specialists have warned that unintentional dozing or overwhelming sleepiness merits clinical evaluation for disorders such as sleep apnea or other causes of excessive daytime sleepiness.

Public‑health authorities also point to the broader risks of sedentary lifestyles. Prolonged physical inactivity has been linked to a range of chronic conditions including obesity, type 2 diabetes, sleep disorders and cognitive decline. Some estimates have attributed tens of thousands of premature deaths per year and substantial health‑care costs to sedentary behaviour in highly industrialised settings.

For most workers, scientists say, the slump is temporary and manageable. Adjusting sleep schedules to ensure adequate night sleep, choosing breakfasts and lunches that emphasize fibre and protein over refined carbohydrates, inserting short bouts of movement into the workday, and, where feasible, taking a brief restorative nap are simple strategies that studies and clinicians say can blunt the early‑afternoon drop in alertness and productivity.