The Relationship Between Vital Capacity and Body Mass
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If you are a large, healthy person, you generally have a higher vital capacity due to a larger chest cavity and larger lungs compared to a smaller, healthy person. Respiratory diseases and a large amount of body fat reduce vital capacity. A large, obese individual with emphysema may have a lower vital capacity compared to a petite, slim person.
Vital capacity is a measure of the maximum amount of air you can forcefully inhale after you forcefully exhale, which is greater than a normal breath. If you are a healthy young man your vital capacity is between 4 and 5 liters; if you are a healthy young woman, your vital capacity is between 3 and 4 liters, according to William McArdle and his colleagues in their book, “Exercise Physiology, Energy, Nutrition & Human Performance.”
Vital Capacity Significance
Vital capacity is especially important during intense physical activity such as exercise, sport, rigorous work or running away from a dangerous situation. Such demands require more air and oxygen in the lungs to fuel body organs, especially those of the musculoskeletal, cardiovascular, respiratory and nervous systems. If you are unfit and overweight, you will not have the lung capacity to increase the volume of air you inhale and exhale beyond normal breathing. You will become out of breath and be unable to perform many activities more difficult than sitting or lying down.
Increase Your Capacity
Obese individuals with a large amount of fat mass typically have weak respiratory muscles and therefore a low vital capacity. Regular aerobic exercise enhances the strength and function of your respiratory muscles, according to 2006 article by James Peterson published by the American College of Sports Medicine. A strong diaphragm muscle and strong external intercostals muscles, the muscles between your ribs, increase your vital capacity by expanding the chest cavity during inhalation.
Increase your vital capacity by decreasing your body-fat composition, becoming more physically active and improving your posture, according to Gary Thibodeau and Kevin Patton in their book, “Anatomy & Physiology.” If you are obese and have asthma or chronic bronchitis, consider exercising in an environment with clean air as pollutants can reduce your ability to take deep breaths during exercise.
Get the Go-Ahead
Increased physical activity for obese individuals can make breathing more difficult due to your deconditioned state, which in turn contributes to a lowered vital capacity. Check with your doctor before you engage in an exercise program to ensure it is safe for you to work out.
- Anatomy & Physiology; Gary Thibodeau, Ph.D. and Kevin Patton, Ph.D.
- Exercise Physiology, Energy, Nutrition & Human Performance; William McArdle, Frank Katch and Victor Katch
- ACSM’s Health & Fitness Journal; Nice to Know Facts About Exercise and Lung Health; James Peterson, PhD
Paula Quinene is an Expert/Talent, Writer and Content Evaluator for Demand Media, with more than 1,500 articles published primarily in health, fitness and nutrition. She has been an avid weight trainer and runner since 1988. She has worked in the fitness industry since 1990. She graduated with a Bachelor's in exercise science from the University of Oregon and continues to train clients as an ACSM-Certified Health Fitness Specialist.