As clocks “fall back” this past weekend, many of us enjoy that extra hour of sleep, but soon we’ll realize that it comes with a cost: darker evenings, shorter days, and a subtle shift in how we feel. Studies found that daylight and mental health are closely linked: noted increases in depressive episodes and mental-health-related hospital visits following the fall time change.
When Daylight Saving Time (DST) ends, we “gain” an hour of morning light, but we also lose daylight in the late afternoon. Suddenly, campus feels darker earlier, practices get cut short, and the sun sets before dinner. These subtle shifts in routine can affect mood and energy more than we might expect.
Research supports this connection. Zhang et al. (2022) identified mental and behavioral disorders as one of four prominent risk clusters, alongside cardiovascular diseases (such as heart attacks), injuries, and immune-related diseases, significantly associated with DST shifts in the United States.* Similarly, a Danish study found an 11% increase in depression cases after the time change, with rates gradually returning to normal after ten weeks. An Australian study also observed increased male suicide rates in the days following both the spring and fall DST shifts.
Why the Time Change Affects Us
Experts believe light plays a powerful role in regulating our circadian rhythm, the internal clock that controls when we feel alert, sleepy, and even how our brain manages mood-related chemicals like serotonin and melatonin. Less sunlight means less stimulation of serotonin, the “feel-good” neurotransmitter, and greater production of melatonin, which makes us sleepy earlier. When our eyes detect natural light, especially in the morning, it sends a signal to the brain’s suprachiasmatic nucleus, the body’s inner clock, to reduce melatonin production and boost serotonin levels. This helps us feel awake, focused, and emotionally balanced. As daylight fades, the process reverses: melatonin rises to prepare the body for rest.
When this natural rhythm is disrupted, such as when daylight hours suddenly shrink after the end of Daylight Saving Time, our brains can struggle to keep up. As our schedules (class times, study sessions, sports practice) stay the same but the daylight hours shift, the body’s internal rhythm gets thrown off, leading to lower energy and irritability.
Studies show that when daylight decreases, many people experience a noticeable dip in mood or energy. For some, the effects are subtle: feeling harder to get out of bed in the morning, groggier during the day, having trouble falling asleep at night. For others, the change can even trigger Seasonal Affective Disorder (SAD), a type of depression linked to reduced sunlight. For students juggling early classes, late-night study sessions, and shifting social schedules, this misalignment can make an already demanding season feel even more draining.
Signs You Might Be Affected
It’s not always easy to tell when the shorter days are taking a toll, but common signs include:
- Feeling unusually tired or sluggish, even with enough sleep
- Losing motivation for school or social activities
- Increased irritability or sadness
- Difficulty concentrating
- Craving more carbohydrates or sugar
If these symptoms last more than two weeks or begin to interfere with daily life, it’s important to reach out for support from a counselor, friend, or healthcare provider.
How We Can Cope
The good news is that there are simple, research-based ways to fight back against the mental slump of shorter days:
- Keep up exercising. Many studies show that exercise and sleep appear “mutually beneficial.” Exercise releases endorphins, which are mood elevators that can help with the No. 1 cause of sleep difficulties: stress. People who consistently exercise see small to moderate improvements in sleep. For that reason, Rebecca Robbins, a sleep scientist at Brigham and Women’s Hospital and an assistant professor of medicine at Harvard Medical School, encourages people to exercise, even if it’s close to bedtime. “If that’s the only time you can get a workout in, go for it.”
- Get morning light. Natural sunlight in the morning helps reset circadian rhythm and boosts mood. When we expose ourselves to light soon after waking up, it signals the brain that it’s time to be alert and active, helping regulate hormones that affect energy and focus throughout the day. Try stepping outside for a short walk before the first class or eating breakfast near a sunny window. Even 10–15 minutes of light can make a noticeable difference. If mornings are dark when you get up, consider using a lamp designed to mimic natural daylight, which can set a positive tone for mood.
- Stay connected. When the days get shorter and darker, it’s tempting to retreat from socializing. But staying connected is one of the most effective ways to combat isolation and provides emotional support. Even brief moments of connection, like a quick chat before class, lunch with a friend, or a group study, can help lift the mood. We may not be able to fill many social events in the schedule, but consistent, meaningful interactions make a big difference.
- Seek help early. Vulnerable individuals (those with SAD, depression, anxiety, stress) are at greater risk for mood worsening when daylight drops. Recognizing these changes early is important, because the sooner we reach out for support, the easier it is to get back on track. Most schools offer counseling services, wellness programs, or peer support groups where you can talk through what you’re experiencing. Sometimes just sharing how you feel can bring relief and help you see next steps more clearly.
The end of Daylight Saving Time can affect more than our clocks, it can influence our energy, focus, and emotional well-being. But by paying attention to our body’s cues, getting outside for morning light, and staying connected with friends, we can ease the transition and protect your mental health. In addition, mental health challenges are common during seasonal transitions, and seeking support is just another way of taking care of yourself. Whether you talk to a counselor, friend, teacher, or family member, opening up early can prevent sadness or stress from deepening and help you find healthier ways to cope as the days grow shorter.
* Zhang H, Dahlén T, Khan A, Edgren G, Rzhetsky A. Measurable health effects associated with the daylight saving time shift. PLoS Comput Biol. 2020 Jun 8;16(6):e1007927. doi: 10.1371/journal.pcbi.1007927. PMID: 32511231; PMCID: PMC7302868.
