As the days draw in and temperatures drop, you may be tempted to hang up your exercise gear and hibernate.
Don't! Stay active throughout autumn and winter to beat those seasonal blues and feel on top of the world.
If you're short on ideas for getting active, try our popular Couch to 5K running plan and Strength and Flex exercise plan, which are ideal for beginners.
And if you're not keen on exercising outdoors, check out:
If you're looking for something less energetic, these strength, balance, flexibility and sitting exercises are ideal if you want to improve your health, lift your mood and remain independent.
Don't worry if you've not done much for a while, these exercises are gentle, easy to follow and can also be done indoors.
Regular exercise will make you feel more energetic, which should make it a little easier to get out of your warm bed on cold, dark mornings.
Your body's defences will also benefit. There is some limited research suggesting that moderate exercise can strengthen the immune system, thereby reducing the risk of coughs and colds.
If the shorter days are affecting your mood, being active can improve your sense of wellbeing. Find out more in Get active for mental wellbeing.
You may be tempted to eat more during the colder months. Exercising will help you manage your weight better and keep your body in shape.
Get tips on eating a healthy balanced diet and taking regular exercise to maintain a healthy body weight.
If you're starting a new exercise regime, don't overdo it. Slowly build the amount of exercise you do. If you can't manage 30 minutes in one go, break it up into 10-minute chunks.
Always warm-up for up to 10 minutes before you start. Walk at a brisk pace, or jog to warm your muscles.
Make sure you're warm if you're going outside. Wear several layers to keep the heat in. A lot of heat escapes through your head, so consider wearing a hat as well.
If you're exercising after dark, keep to well-lit areas and wear bright and reflective clothing. Ideally, exercise with a friend, but always tell someone where you're going.
Avoid listening to music while running outdoors. Not hearing what's going on around you can make you vulnerable.
If rain or ice is making exercise dangerous, do it another day. The weather might be better tomorrow, but an injury could take weeks to heal.
If you have a cold
Colds are more common in winter, but you don't necessarily have to stop exercising if you're feeling under the weather. According to Dr Keith Hopcroft, a GP from Basildon in Essex, use common sense and listen to your body.
"If your symptoms are not severe and you generally feel OK, then you can exercise. If you feel absolutely rotten, then it's best not to go."
However, it is important not to exercise if you have a fever. A fever is when your body's temperature is 38C (100.4F) or above and is rarely a symptom of a cold.
"If you exercise with a fever," says Dr Hopcroft, "it'll make you feel worse. In very rare cases, exercising with a fever can lead to the virus affecting your heart, which can be dangerous."
If you have asthma, take extra care when exercising in winter as cold air can trigger symptoms. Use your inhaler before you exercise and have it with you during your activity.
Something you enjoy
Choose an activity that you enjoy. Now might be the time to try something new that you can do indoors, such as tai chi, yoga, rock climbing or swimming.
Use our directory to find fitness activities and classes near you.
You don't even have to stop doing outdoor activities.
If you enjoy running, don't let cold weather put you off. Get tips on running outdoors in winter.
You could take a long walk at the weekend or go for a bike ride. Just wrap up warm and be careful if it's wet or icy.