The most effective exercise programs engage all the major muscle groups. You should exercise regularly for the health benefits, and to improve your quality of life and your ability to perform everyday tasks. You can measure the effort of your workouts through heart rate. Your heart rate will vary, depending whether you exercise the smaller muscle groups of your arms or the larger muscles of your legs.
The cardiovascular system performs several vital functions during exercise, and these are reflected in your heart rate. Whether you are exercising your upper or lower body, your body still must supply adequate amounts of oxygen and nutrients to fuel muscles in motion. Your metabolism removes waste products and transports heat throughout your body. When you work your legs, you are working larger muscle groups, which require more fuel and oxygen. Your heart rate will be higher when exercising your legs than it is when you exercise your arms simply because of the greater demand caused by the larger muscles.
In addition to the number and size of muscles, other factors influence your heart rate when working your arm or leg muscles. Proper breathing technique during exercise helps you avoid large spikes in blood pressure and heart rate. A 1995 study by Loma Linda University found that heavy weightlifting elevated blood pressure dramatically, even in small muscle groups such as those in the arms. Researchers recommended correct breathing technique as a safe way to allow the body to cope with the associated blood pressure increases.
Your body will adapt to regular arm and leg exercises by increasing its efficiency. Your heart will increase in size and strength so it can deliver oxygen and fuel more quickly. The variations and elevations in heart rate during upper and lower body workouts may become less evident. Your resting heart rate will be lower, and you will recover more quickly from exercise. To continue to build strength and improve cardiovascular fitness, you will need to increase the intensity of your workouts through use of heavier weights or more repetitions.
When doing arm and leg exercises, focus on a particular order to avoid fatiguing your muscles too soon. You should begin with the larger muscle groups and work down to smaller muscles. For your arms, focus on exercises such as the shoulder press before moving on to bicep curls. For the legs, follow a similar pattern by concentrating first on exercises that target your quads and hamstrings before moving to exercises focusing on your lower legs. You will be able to do a more complete workout this way.