On top of that, exercise enhances immunity, lowers blood pressure and cholesterol, and triggers the release of endorphins, your body's natural painkillers. Perhaps most important, exercise boosts self-confidence and helps you gain command over your health.

What Happens When You Don't Exercise?

The avoidance of exercise perpetuates a cycle that leads to greater fatigue, less activity, and more weight gain. The less you move, the weaker and smaller your muscles become. And as your muscles get smaller and weaker, your joints will become stiffer and increasingly inflexible, making it even harder for you to get the physical activity you need.

The lack of exercise can also worsen your depression, which is common in hypothyroidism. Feeling depressed, in turn, can make it harder to exercise. Next thing you know, you're trapped in a vicious cycle of fatigue, depression, and a lack of exercise, all of which can lead to unwanted weight gain.

That's why it's critical to always do some physical activity every day, no matter how little or how insignificant it may seem. Even short walks around the block can improve your mood, relieve your fatigue, and help you sleep better. If it's been a while since you exercised, it's best to talk to your doctor first before launching an exercise program.

Build Those Muscles

Chances are, when you think of strength training, you probably think of big, bulky men — or women — with bulging muscles. But in reality, strength training isn't only for the muscle-bound. Building muscle can benefit anyone who wants to maintain vitality, improve conditioning, and build more strength. And having more muscle mass helps ensure that you burn more calories, even at rest.

For people with hypothyroidism, strength training is important because it can help boost metabolism. The extra muscle will help keep your metabolism at a higher rate than it would if you had no muscles. And the higher your metabolism, the less likely you are to gain weight.

Certain types of strength training may be better than others for different people. The strength-training exercises you should know include:

Cardiovascular Exercise

Whether it's a brisk walk, a long bike ride, or a kickboxing class, anything that gets the heart pumping can strengthen your heart and increase your endurance. When you engage in cardiovascular exercise, you breathe harder, so your lungs are working harder, too. These exercises also improve blood flow; aid in weight loss; and lower blood pressure, triglycerides, and LDL cholesterol, the bad cholesterol. In addition, cardio workouts can minimize depression, reduce stress, and improve sleep — all of which help stave off weight gain and perpetuate weight loss.

For someone who has hypothyroidism, getting a cardiovascular workout might seem too daunting, especially if you're new to exercise. The thought of even driving to a pool might seem too exhausting, much less getting in and swimming laps. That's why it's important to choose your cardio workout carefully. When you're in the throes of serious fatigue, it'll be hard to muster the energy for a rigorous aerobic workout. Instead, look for low-impact activities that you really enjoy. The pleasure of an activity will help ensure that you'll do it again, day after day.

A Word on Walking

One of the best cardio exercises you can do is walking. It's safe, convenient, and easy, and requires no special equipment. It doesn't involve a pricey gym membership, and you can do it virtually anywhere. You don't even need any special training. All you do need is a good pair of walking shoes. Walking is also unlikely to cause injuries that might deter you from exercising in the future.

If you decide that walking is the best exercise for you, then by all means, give it a try. Always wear a good pair of well-fitting shoes that provide adequate support. Replace old shoes that are unevenly worn, which can cause an imbalance in your footing and lead to muscle pain.

When you do start walking, go slowly and resist the urge to walk lengthy distances. If you feel stiff, do some gentle stretches before heading out. Don't push yourself too hard, which can lead to injuries that interfere with workouts. Exercising regularly is more important than getting a single strenuous workout.

While you walk, make sure to breathe as normally as possible. To stay safe, walk in well-populated areas or carry a cell phone, in case of emergency. If it's hot, carry a water bottle so you can stay hydrated. Finish the walk with a cool-down walk and some gentle stretching.