Why am I so tired all the time? Understanding fatigue in the winter months


4 minutes

27 May 2024

Are you finding yourself constantly tired, even though you're getting what feels like enough sleep? You're not alone. As the winter months approach, many of us experience increased fatigue.

In this blog, we'll explore the various factors that can contribute to winter fatigue, including the role of vitamin D, seasonal affective disorder (SAD), reduced physical activity, and more. Plus, we’ll provide tips on how to combat fatigue and boost your energy levels.

Seasonal changes and vitamin D deficiency

With shorter days and less sunlight during winter, our bodies absorb less vitamin D, which is essential for maintaining energy levels1 and overall well-being, including bone health2.

While not as effective as careful sun exposure, there are a number of dietary sources that can boost your vitamin D intake during winter, including mushrooms (vitamin D2), as well as liver and oily fish including tuna, salmon, mackerel and herring and egg yolks (vitamin D3)3.

If you’re feeling tired and suspect you may have a vitamin D deficiency, your GP can confirm with a simple blood test2. From there, they can recommend the appropriate supplement to help get your levels back up and have you feeling your energised self again.

Seasonal affective disorder (SAD)

Seasonal affective disorder, more commonly known as SAD, is a type of depression that occurs seasonally, typically during the autumn and winter months4. Symptoms include fatigue, low mood, irritability, and changes in appetite or sleep patterns5.

SAD is thought to occur due to a lack of sunlight which can disrupt the body's internal clock (circadian rhythm) and production of melatonin and serotonin4. Light therapy, seeing a psychologist, taking vitamin D supplements, getting out and about, and maintaining regular exercise can be effective in managing SAD symptoms4.

Reduced physical activity

With colder weather, darker mornings and shorter daylight hours, the temptation to snuggle in and sleep through your alarm or crash on the couch after work can be hard to resist. While regular exercise obviously expends energy, conversely it also boosts energy levels, improves sleep quality, and helps to alleviate symptoms of fatigue6.

During winter, there are plenty of alternatives to working out outside, including joining an indoor sports team, hitting the gym or exercising at home.

At HBF, we have you covered (pardon the pun) with our Workout well at home and Yoga by Megan online series which allow you to tune in and work out when it suits you.

Or, if the gym is more your style, HBF members get awesome discounts at a number of gyms. To view current offers, visit our Member Perks page.

Not enough sleep

Changes in routine, shorter days, and colder temperatures can all disrupt sleep patterns, leading to poor sleep quality and increased fatigue7. In addition, new research has shown that REM sleep (rapid eye movement), known to be directly linked to our internal circadian clock, tends to last 30 minutes longer in the winter than in summer, suggesting we may need to consider slightly more sleep in the winter months in order to feel well-rested8.

If you’re struggling to get quality sleep during winter, we recommend maintaining a consistent sleep schedule, exercising during the day, creating a relaxing bedtime routine, and keeping out of the bedroom unless you’re sleeping9. The Australian Sleep Health Foundation (SHF) recommends aiming for 7-9 hours of quality sleep each night to give your body the rest it needs to stay strong and resilient10.

Maintaining a healthy diet

As the weather gets colder, the urge to turn to comfort food gets that little bit harder to ignore. However, maintaining a healthy diet of foods high in antioxidants, protein, fibre, vitamins B, C, D and E, and low in sugars and fats will not only help you give you more energy, but it will also help you recover more quickly if you fall ill11.

The CSIRO recommends incorporating plenty of fruits, vegetables, whole grains, and lean proteins into your meals to provide your body with the essential vitamins and minerals it requires to function properly11.

For some awesome ideas on cooking with winter veggies (hello brussel sprouts, kale and broccolini), check out our blog.

Feeling tired during the winter months is a common experience for many people, but it doesn't have to be unavoidable.

By understanding the various factors contributing to winter fatigue and taking proactive steps to address them, such as incorporating vitamin D-rich foods, staying active, maintaining a healthy diet, and seeking support if needed, you can combat fatigue and thrive during the colder months.


1North American Journal of Medical Sciences: Correction of Low Vitamin D Improves Fatigue: Effect of Correction of Low Vitamin D in Fatigue Study (EViDiF Study)

2Healthdirect: Vitamin D and your health

3Healthdirect: Sources high in vitamin D

4Healthdirect: Seasonal affective disorder (SAD)

5National Institute of Mental Health: Seasonal Affective Disorder

6Healthdirect: Exercise and mental health

7Sleep Health Foundation: Understanding and Helping Poor Sleep

8Frontier in Neuroscience: Seasonality of human sleep: Polysomnographic data of a neuropsychiatric sleep clinic

9Healthdirect: How to get better sleep, according to science

10Sleep Health Foundation: How much sleep do you really need?

11CSIRO Total Wellbeing Diet: The best diet for the immune system


This article contains general information only and does not take into account the health, personal situation or needs of any person. In conjunction with your GP or treating health care professional, please consider whether the information is suitable for you and your personal circumstances.