What is VO2 max? And why is it so fascinating?
VO2 max holds gold standard status by medical experts in determining physical fitness. Scientifically defined as maximal aerobic capacity, it is an excellent method to calculate your fitness levels. VO2 max measures the maximum rate of oxygen consumption during high intensity activities.
What’s so fascinating about VO2 max is that it can be used to calculate the amount of oxygen your body uses during exercises. Maximum oxygen intake is determined by taking into account the heart, lungs, blood, and skeletal muscles, which are all used during activity. VO2 max is important for the following reasons:
- Measures oxygen your body uses at maximum effort
- Evaluates lung function and health
- Best overall indicator of physical fitness
- Can also give an estimate of miles per run for runners
- Trainers and doctors can use it as a benchmark to design training programs
- It is a helpful and accurate tool for predicting life expectancy
- It can help uncover certain respiratory and cardiac diseases
- Used in health examinations to identify and stratify the risk of heart ailments
Improving VO2 max decreases mortality rate
- Having a higher VO2 is also associated with greater mitochondrial density. The mitochondria are found within the cytoplasm of the cell and produce very large amounts of ATP, or energy. As our VO2 goes up, the density of mitochondria within the cells increases. This increase leads to an increase in the body’s efficiency to deliver oxygen and nutrients to working tissue.
The effect of an improved VO2 max on the physiological parameters of the breathing system
- Increases the amount of carbon dioxide expelled per minute. Carbon dioxide expelled (VCO2) is the volume of the exhaled CO2 per minute, given in mL/min/kg.
- Increased ventilation increases oxygen consumption until a threshold is reached at which body processes start limiting it. Ventilation (VE) is the volume of air inhaled or exhaled from a person’s lungs, given in liters per minute.
- During aerobic exercise, tidal volume increases. The tidal volume of an unfit individual will be smaller than that of a well-trained/fit/healthy individual. Tidal volume (VT) is the volume of air exhaled in one expiration or inspiration, given in liters.
- Intense exercise can increase breathing rates up to 40 to 50 breaths per minute. Respiratory rate is how many breaths you take every minute. The normal respiration rate for an adult at rest is 12 to 20 breaths per minute.
- It is generally believed that a lower heart rate at rest indicates better heart function. With increased fitness, the body is able to transport oxygen more efficiently. Every time the heart beats more blood is pumped as its resting heart rate decreases. The normal resting heart rate (bpm) for adults ranges from 60 to 100 bpm.
- A respiratory exchange ratio (RER) is the ratio between carbon dioxide (CO2) produced by metabolism and oxygen (O2) consumed, and Lactate Threshold (LT) refers to the point at which, as a breakdown product of carbohydrates, lactate accumulates more rapidly in the blood creating a feeling of heaviness in the muscles. These 2 useful values are also determined during VO2 max. Lower RER indicates that more oxygen is used compared to carbon dioxide released. Hence, fats are broken down more quickly than carbohydrates. With a RER of 0.85, approximately 50% of the fat and 50% of the carbohydrate is broken down. If the RER is more than 1, then mainly carbohydrates are being broken down. In general, LT corresponds with a RER of 1.0. Through fitness training, you can decrease the RER value as you develop your body’s ability to use fat as a fuel source, thus saving limited carbohydrate sources.
How can you calculate your VO2 max?
VO2 max is expressed in metabolic equivalents (METs) or mL/kg/min. A MET represents the body’s ability to use oxygen, whereas a VO2 max represents its ability to deliver oxygen during physical activity.
VO2 max is a measure of how much oxygen your body can use per kilogram per minute. There are many methods to calculate VO2 max, the common ones use a treadmill or cycle ergometer, both of which calculate how much energy is spent. There are non-laboratory-based protocols for estimating VO2 max such as the Cooper 12-minute run test and the Bruce protocol.
Today, most modern devices have inbuilt features such as a heart rate monitor that help to calculate VO2 max values. Your maximum heart rate is used to calculate VO2 max.
A good VO2 max for a 25-year-old male is 42.5-46.4 mL/kg/min, while a good value for a 25-year-old female is 33.0-36.9 mL/kg/min.
The chart below are the poor to superior VO2 max values for men and women. It is important to note that VO2 max differs with age, gender, fitness levels and body composition. Hemoglobin levels, heredity and fitness training are a few more factors among many others that affect VO2 max.
Interesting research studies on VO2 max
Interesting research suggests that VO2 max predicts longevity. Studies have revealed that individuals with heart disease and a higher VO2 max lived longer than those with no heart disease and a lower VO2 max.
An article published by Anette Melk and colleagues in the International Journal of Cardiology speaks of improvement of biological age with physical activity. This means VO2 max can be improved with exercise, improving biological age. The research findings indicate that if exercise starts even later in life, it significantly reduces chances of early death since the body’s cells stay healthy for longer.
Research also suggests it is possible to increase mitochondrial density by High Intensity Interval Training (HIIT) at VO2 max intervals. Stimulation of mitochondrial biogenesis increases their enzyme functions. The mitochondrial enzymes help to improve skeletal muscle metabolic function.
Understanding your VO2 max and getting your VO2 max values will help you estimate how healthy you are, predict information on your biological age, endurance and fitness. You can understand the physiological parameters of the breathing system and ultimately use all the information to bring about lifestyle changes for a healthier you!
How can you improve your VO2 max?
- VO2 max decreases with age. Also, males have a higher capacity to utilize O2 than females. With factors such as these in mind, one can train to increase their VO2 max
- The goal of training is to increase the amount of blood your heart can pump, thereby increasing the amount of O2 your muscles can take in.
- Exercise is key to improving your VO2 max. By gradually increasing the intensity of your training exercises and training in intervals, you can work toward improving your VO2 max.
- It is good to start with simple aerobic exercises such as running, cycling or swimming. Even walking for some individuals is a good start. As pace builds up more intense exercises can be done.
- Cardiovascular exercises strengthen the heart and increase VO2 max. In turn, this increases the heart’s ability to pump oxygen to the muscles.
Contemplating about getting your VO2 max assessed? It’s important to know. Check out our programs and evaluation. Visit our website for more information, as well as to book your free consultation.
Contributor: Rudy Inaba Vice President of Health Performance
Rudy Inaba is Cenegenics’ Vice President of Health Performance. He is a recognized ﬁtness and sports nutrition consultant with nearly 15 years of experience in clinical exercise physiology and lifestyle management. After pursuing his Master of Science in Clinical Exercise Physiology at the University of Nevada Las Vegas, Rudy joined Cenegenics where he leads 19 clinical locations nationwide in their advancements in kinesiology, nutritional biochemistry, and their analyses of industry research & market trending.