Fitness Insights: Information, Observation, and Experience – Gretchen M. Ashton

What happens to the body when diving?

• Immersion reduces vital breathing capacity by about 10%.
• Shifts in breathing patterns occur in the majority of divers from dry to wet.
• Diving equipment affects breathing and adds physiological workload.
• On the surface, the heart is often the limiting factor. At depth, the respiratory system becomes more limiting.
• Loss of just a couple of degrees of core body temperature can increase VO2 to two to five times resting levels.
• Younger, leaner, or more aerobically fit divers produced fewer bubbles compared with older, those with higher body mass, or lower aerobic fitness.
• Doubling frontal surface area can result in four times the original resistance. Divers with a larger physical profile, regardless of fitness level, may therefore expend significantly more energy to maintain the same speed..
• Higher levels of body fat may be a contributory factor in decompression stress and related risk.

The Health Profile of the Diving Community

Summarized by a 20-year review of “Medical Conditions Reported by Divers” and case studies, includes the following in order of prevalence: Heart Disease / Cardiovascular Conditions, High Blood Pressure, Obesity, Diabetes, Smoking, Asthma, Allergy.

Divers also reported musculoskeletal issues such as back pain, shoulder injuries, knee problems, and arthritis, as well as injuries related to accidents or prior military service. Psychological conditions, including stress and panic, were also noted.

This health and medical information is fairly consistent with the general population. The good news is that many of these conditions can be prevented and corrected with even moderate exercise and nutrition guidelines.

Benefits of Fitness for Diving

Notice how these benefits of exercise correlate to the medical conditions reported by divers.

• Improve Cardiorespiratory Health
• Prevent and Manage Heart Disease and High Blood Pressure
• Lower High Blood Pressure through Lifestyle Modification
• Burn Fat and Promote Healthy Weight Loss
• Prevent, Reverse, Manage and Reduce the Long-Term Effects of Diabetes
• Assist in Smoking Cessation
• Reduce the Symptoms of Asthma and Allergies
• Prevent and Reverse Bone Loss

So why do surveys consistently show that fewer than 30 percent of divers participate in a regular exercise program? In the United States alone, there are approximately three million divers, about 77 million gym memberships, and roughly 247 million people who report participating in at least one physical activity. These numbers suggest that fitness-minded individuals already exist within many dive communities. Often, it is simply a matter of awareness and conversation.

Public health data from organizations such as America’s Health Rankings shows that rates of hypertension vary by region, influenced by factors such as lifestyle patterns, access to healthcare, and broader social conditions.

Large population studies referenced by the National Institutes of Health show that hypertension and other cardiovascular risk factors are common across adult populations, affecting roughly one in three adults. While prevalence varies slightly between men and women, the broader takeaway for the diving community is clear: cardiovascular health is strongly influenced by modifiable factors such as physical activity, overall fitness, and lifestyle choices. For divers, maintaining physical preparedness supports safety, comfort, and long-term participation in the sport.

Exercising to enhance recreational activity is a positive way to take responsibility for personal health, bring focus and motivation to a fitness routine, and improve the overall diving experience. For dive store owners and instructors, physical preparedness also supports professional credibility, endurance, and the ability to lead and supervise others with confidence. Framed appropriately, fitness awareness becomes another tool for supporting diver safety, enjoyment, and long-term participation in this incredible recreational and professional sport.