You might associate cardio with tiredness, the feeling you get after a run, a bike ride or a tough aerobics class. Even though a hard workout can leave you exhausted over the long term, cardio is critical to improving your health and fitness, which will give you more energy in your everyday life. Cardio gives you energy in specific ways, but the type of cardio isn't important --- just get out there and get your heart pumping. Consult your doctor before starting a vigorous exercise program.
Cardio exercise gets your heart pumping, which is one of the key ways it helps give you energy. According to "Your Best Body Ever," as your heart adapts to the demand of cardio it grows stronger, meaning that when you are resting your heart doesn't have to beat as often to circulate blood. Thus, your resting heart rate lowers, reducing the demands on your body and leaving you with more energy. This becomes a positive feedback loop where increased energy boosts your workout so you build more endurance and have more energy to spare.
Cardiovascular exercise is energizing because it trains your body to use oxygen efficiently, according to fitness training guide "You Too Can Succeed." Even moderate cardio such as walking or taking the stairs will help your heart and lungs become more efficient at absorbing oxygen from the blood, meaning you have access to greater reserves of oxygen. This prevents feelings of tiredness or weakness due to lack of oxygen.
In "Exercise Therapy in the Management of Musculoskeletal Disorders" author Fiona Wilson-O'Toole reports that poor cardio fitness is linked to muscular injuries such as ankle sprains. Though it is not clear exactly why this is, it may be because cardio workout such as running, biking and swimming also support muscle building. Greater muscular fitness, along with the beneficial effects of cardio in supplying more oxygen to the muscles, means your energy and endurance improve.
Cardio has many long-term benefits for energy, but it also supplies a quick burst of energy in the form of feel-good chemicals called endorphins. "Move To Lose" notes that when you do cardio your brain releases endorphins, which lift your mood and alleviate feelings of pain and stress. They are responsible for the phenomenon known as "runner's high," where you feel energetic or even euphoric after doing a tough cardio workout. This makes cardio an ideal way to beat the blues, or give you a boost after a tough day.