Seasonal Affective Disorder (S.A.D.)
Seasonal Affective Disorder (S.A.D.): How Winter Affects Your Mood, Sleep, and Health
It’s late May in Melbourne. The days are shorter, the sunlight is fading, and the crisp mornings make it harder to get out of bed. Maybe you’ve found yourself hitting the snooze button more than usual, skipping the gym, or feeling less motivated and more down than normal.
If this sounds familiar, you may be experiencing Seasonal Affective Disorder (S.A.D.) — a form of low mood or depression that commonly occurs during the colder, darker months.
What Is Seasonal Affective Disorder?
S.A.D. is believed to stem from the reduction in natural sunlight during late autumn and winter. The lack of light triggers a series of chemical changes in the brain, affecting the hormones responsible for mood, sleep, and energy.
These changes can lead to:
Fatigue and lethargy
Low mood or irritability
Difficulty concentrating
Disrupted sleep patterns
Loss of motivation
In particular, insufficient light exposure can cause:
Decreased melatonin production — the hormone that regulates sleep.
Reduced serotonin levels — the “feel-good” neurotransmitter responsible for mood and energy.
When these hormones fall out of balance, you may struggle to sleep soundly and wake refreshed — and poor sleep has a direct impact on your mental and physical health.
The Importance of Sleep and Sunlight
Your circadian rhythm, or body clock (“circa” = around, “dia” = day), operates on a 24-hour cycle. Reduced sunlight exposure in winter can disrupt this natural rhythm, confusing your sleep-wake patterns and energy levels.
Compounding this is the issue of Vitamin D deficiency, which becomes common during colder months when we spend more time indoors. Vitamin D is essential for bone health, immune function, mood regulation, and even serotonin production.
Low Vitamin D levels have been linked to:
Increased risk of osteoporosis
Higher likelihood of cardiovascular disease
Cognitive decline
Worsened symptoms of depression and low mood
What You Can Do to Combat S.A.D.
The first and most important step is to recognise that these feelings are normal and temporary — and you are not alone. With a few proactive steps, you can take control of your mood, sleep, and health this winter.
1. Get Outside and Seek Sunlight
Try to spend time outdoors each day, even for short walks.
Expose your skin to sunlight when possible to boost Vitamin D.
Fresh air and light movement also help lift mood and energy levels.
2. Maintain a Consistent Routine
Go to bed and wake up at the same time every day (even on weekends).
Stick to regular meals, exercise, and work routines to stabilise your body clock.
If you missed it, check out our previous blog on sleep — consistency is king.
3. Support Your Body with Vitamin D
Speak to your GP about testing your Vitamin D levels.
Supplement appropriately if deficient.
Combine this with balanced nutrition and hydration.
4. Prioritise Physical Health
Regular osteopathic treatment can help reduce physical discomfort that compounds fatigue and low mood. Osteopathic care can:
Ease tightness and stiffness that drain energy.
Improve joint mobility and muscle flexibility.
Support circulation and nervous system balance.
Feeling better physically can make it easier to stay active and maintain motivation throughout winter.
If you’re feeling flat, fatigued, or noticing more tension through your neck, back, or shoulders this winter, our experienced South Yarra osteopaths at Osteopathic Movement can help. We take a holistic approach to support your mood, mobility, and overall wellbeing through hands-on treatment and lifestyle guidance at our Osteopathic Movement wellness centre. Book your appointment online and take proactive steps toward feeling your best this season.
Written by Dr Dayne Sweres (B.AppSci (CompMed), M.Osteo) – Founder, Osteopathic Movement, South Yarra.