Blog

At Coyne Medical, we are incredibly passionate about the use of exercise as medicine. A huge amount of medical evidence now shows that low levels of fitness are associated with an increased risk of dying from any cause, including heart and vascular disease and cancer rates. In comparison to smoking, having high blood pressure, high cholesterol, or type 2 diabetes mellitus, fitness is a stronger predictor of death. The fitter you are, the lower your chance of dying. The addition of fitness metrics to the standard medical risk variables enables medical professionals to more precisely categorise your disease risk. Being unfit is a massive risk factor for disease. 

Higher fitness levels are not only associated with a lower risk of death. High fitness is also associated with a lower risk of chronic diseases. The least-fit and next-least-fit groups of people have the most to gain from increased fitness. With increased fitness, these groups have seen a massive reduction in adverse health outcomes. Indeed, bringing VO2 max from the “low” range to merely “below average” reduces mortality by 50%! So there is no need to come anywhere close to the world record of the highest VO2 max of 96.7 ml/kg/min. This highest-ever VO2 max was achieved by Norwegian cyclist Oskar Svendsen. Their cardiovascular risk also declines substantially with increased fitness. Ideally, all adults should have their fitness measured on a regular basis, just like any other preventative check, such as checking blood pressure. The most accurate way to measure your fitness is through a VO2 max test.

Higher fitness levels are not only associated with a lower risk of death. High fitness is also associated with a lower risk of chronic diseases. The least-fit and next-least-fit groups of people have the most to gain from increased fitness. With increased fitness, these groups have seen a massive reduction in adverse health outcomes. Indeed, bringing VO2 max from the “low” range to merely “below average” reduces mortality by 50%! So there is no need to come anywhere close to the world record of the highest VO2 max of 96.7 ml/kg/min. This highest-ever VO2 max was achieved by Norwegian cyclist Oskar Svendsen. Cardiovascular risk also declines substantially with increased fitness. Ideally, all adults should have their fitness measured on a regular basis, just like any other preventative check, such as checking blood pressure. The most accurate way to measure your fitness is through a VO2 max test. 

VO2 Max Testing

VO2 max testing is a form of cardiopulmonary exercise testing (CPET). It is a method used to assess the performance of the heart and lungs at rest and during exercise. VO2 max testing is totally non-invasive. During the test, information about the heart and lungs is collected to understand if the body’s response to exercise is normal. 

VO2 max, or maximal oxygen consumption, refers to the maximum amount of oxygen that an individual can utilise during intense or maximal exercise. This measurement is generally considered the best indicator of cardiovascular fitness and aerobic endurance. The more oxygen a person can use during high-level exercise, the more energy a person can produce. This test is the gold standard for determining fitness because the muscles need oxygen for prolonged aerobic exercise and the heart must pump adequate amounts of blood through the circulation to meet the demands of the exercise. There is a strong association between VO2 max and longevity. Thus, knowing VO2 max gives us a powerful metric that we know is associated with longevity and that we can objectively improve. That’s right, we can improve our VO2 max. 

The benefits of VO2 max testing

Aside from providing the impetus to get fitter in order to live longer, there are several reasons why VO2 max testing is so important:

• Your current fitness can be accurately measured. This allows doctors to accurately classify your risk of a whole host of diseases. 
• It allows the capability to create a really efficient, bespoke training programme tailored to you. 
• It allows the evaluation of the effectiveness of a training programme 
• It can establish what is optimal running speed or cycling wattage to maximally improve endurance fitness and optimally burn fat
• It can assist in distinguishing causes of low fitness from cardiac or pulmonary causes
• From a doctor’s perspective, it can be used to provide helpful prognostic information in those suffering from chronic diseases

The data obtained from VO2 max testing enables the most precise and standardised quantification of fitness. The primary advantage is the direct measurement of fitness. This is  as opposed to estimating peak or maximal VO2. Establishing exercise intensities (training zones) based on VO2 max testing allows athletes to minimise the risk of injury and fatigue while also enhancing adaptations and responses to the training plan. 

Older athletes, or those with underlying medical conditions, can also benefit from VO2 max testing. This is because it can provide risk stratification for disease. It also allows safe clearance to participate in sports events. VO2 max can also be used to set training zones and determine exercise limitations for older athletes.

How VO2 Max is measured

By putting on a face mask, the volume and gas concentrations of inspired and expired air can be directly measured. This measure is often used in research and is considered the most accurate. The test involves either exercising on a treadmill or a stationary bike. The intensity increases every few minutes until exhaustion. Thus, it is designed to achieve maximal effort. 

What You Can Learn From VO2 Max Testing

VO2max testing provided several different metrics that are incredibly useful. 

• VO2Max

• This is the maximum amount of oxygen that an individual can utilise during intense or maximal exercise. 

• As mentioned earlier, there is a strong association between VO2 max and longevity. 

• • • It defines the exercise limits of the heart and lungs in healthy people.
    • It decreases with age, 8%-10% per decade in trained individuals who continue to train vigorously. 
    • Men have a VO2 max that is 10%-20% higher than women.

• Ventilatory Threshold (also known as lactate threshold/ VT1)

• • • Anaerobic (without oxygen) metabolism occurs when muscle energy demands exceed oxygen delivery to the muscles.
    • As anaerobic metabolism begins, the breathing rate and breathing effort increase to aid in CO2 removal from the body.
    • At this point, blood lactate levels start to rise, VO2 levels peak, and CO2 production accelerates. Rising lactate levels inhibit performance. So our muscle’s ability to utilise and clear lactate is very important. Training at low intensity helps us clear lactate efficiently. 
    • The measurement sets the upper limit of low-intensity training. 
  • The peak respiratory exchange ratio
    • This is the objective measure of the maximal effort of the participant 
    • It has a huge advantage over estimated maximal heart rate (HRmax), which is often derived from the commonly used equation 220-age
    • When estimated, maximal HR has a large population error of up to 12 bpm and thus is not an ideal indicator of exercise effort
    • Fitness levels have also been shown to influence the decline in maximal HR with age making HRmax even more unreliable. 

• 2nd Ventilatory threshold (Anaerobic Threshold)

• • At this point. lactate has quickly accumulated in the blood, necessitating heavy breathing to expel CO2.
  • This represents the transition point between moderate and high-intensity exercise.
  • Thus, it sets the limits of high-intensity training

Implications for Exercise

Knowing the right intensity to exercise at enables you to maximally improve your fitness performance. Polarised training has been shown to lead to the greatest improvements in endurance performance. This type of training consists of mainly low-intensity, high-volume training (75%).  There is a moderate amount of high-intensity or sprint interval training (20%), and a small amount of training at threshold intensity (5%). Establishing your VT1 and VT2 will help you get the most out of your training. What you can measure, you can manage.  VO2 max is the most accurate way to measure your fitness, and maintaining a high VO2 enhances longevity.  

Dr Hugh Coyne

Private GP

Parsons Green