VO2- What?



Many people outside of the health and fitness world may just say VO2-what? upon hearing the term VO2max or VO2max testing. In this article you will gain knowledge of what the VO2max level is, how it is tested, and how it can be used for anyone.

VO2max is an abbreviated term for volume (V) of oxygen (O2) used at maximal effort. It is the highest rate of oxygen consumption attainable during maximal or exhaustive exercise (think the last leg of a race). The VO2max is the best indicator of cardiovascular fitness and aerobic endurance.

VO2max is measured as ml·kg-1·min-1. Examples of a non-athlete’s VO2max level for a male between the ages of 30-39 is 39-48 ml·kg-1·min-1; a female in the same age range is 30-38 ml·kg-1·min-1. The highest VO2max level recorded was from a cross-country skier (90.0 ml·kg-1·min-1).

Aerobic vs. Anaerobic

Oxygen is important- we not only need it to breathe, but also it plays an important role in how our bodies produce energy (ATP) that is used for all activity. When oxygen is present during an activity to create ATP through the breakdown of nutrients it is an aerobic activity. Examples of aerobic activities include walking, running, and swimming. When oxygen is not present to help create ATP it is an anaerobic activity. Examples of anaerobic activities include sprinting and heavy resistance lifting.

butterfly-swimmingAs you exercise, or more specifically increase the effort of exercise, the more oxygen you consume. Aerobic activities can be performed at a steady pace over a period of time with minimal change in your breathing rate (unless you change speed or resistance).

For endurance athletes one of their goals is to use their oxygen in the most efficient way possible over the length of a race. During the last bit of a race, more effort will be used in order to drive their final bursts of speed and strength to the finish line. This last kick is where the VO2max comes into play- the athlete is taking up oxygen at a maximal level while sustaining a maximal effort. The more efficient an athlete’s VO2max is, the longer they can sustain this all-out effort. While performing this all-out effort the body will fatigue quickly as the energy stores are rapidly depleting and forcing the body to switch to anaerobic function.


VO2max Testing

VO2max testing measures the amount of oxygen used in one minute of maximum effort per kilogram of body weight (ml·kg-1·min-1). The testing is performed on a piece of stationary exercise equipment (a bike or treadmill), a heart rate monitor, a specialized mask that is used to measure your breath and its components, and a software program on a computer. At XpertHealth we utilize a stationary bike for our testing and the Cortex testing system.

At XpertHealth we use a Bluetooth Heart Rate monitor which is worn around the torso. The mask will cover the nose and mouth for the entirety of the test and is connected to a unit that will measure your breathing and the components of your breath. All of the equipment will send real time data to the computer where the program will analyze the data. The data that is created during the test includes the respiratory exchange ratio (amount of oxygen used to the amount of carbon dioxide exhaled), oxygen consumption, breathing rate and volume, and other measurements.

640_480_metalyzer-3b-r3_1The test itself lasts between 10-15 minutes. As the test progresses you will have to increase your effort as resistance is automatically added. Towards the end of the test you notice that your breathing has increased and you are starting to feel fatigue. The test can be stopped at any time, but concludes after your maximal effort is exerted.

Following the cool down period, the tester will go over your results with you. Based on the data a customized training program can be created to help meet your goals. Follow-up or re-tests are recommended every six weeks during your training cycle.


How Can the VO2max Be Increased?

A VO2max level can be improved through modifying your current training program or simply by starting one. Training intensity and volume are increased; and some days may focus more on speed or pace while others focus more on distance. For each work out there will be target heart rates to follow that based on the results of the VO2max test.

Not everyone will show the same improvements. Those who are trained may only see small improvements versus those who are untrained who will show large improvements. Average rates of improvement range from 5%-20%.

Factors such as genetics, sex, and age can affect the VO2max levels. One thing that can be changed is the environment in which you train in. Areas with a high Air Quality Index will see a lower VO2max level. However, training indoors in an environment with good air filtration (such as your home) can eliminate the effects of air pollution and help increase the level.

Uses for a VO2max Test Result

VO2max testing isn’t just for athletes who want to improve their performance, but rather anyone regardless of fitness level. VO2max can be used to help develop weight loss programs, monitor fitness levels, help with nutrition guidance, and help identify potential health problems.

The target heart rate zones can help create different fitness programs. For weight loss these zones can help identify what intensity and session duration will have the most impact on burning calories while improving the cardiovascular fitness level. This also helps to improve body composition and change one’s view about their body.

Medically the VO2max can help identify potential health issues with the heart and lungs and the need for additional testing. For example, if someone has a high oxygen uptake at a low intensity they may have an issue with their lungs or heart. These issues could be a potential blockage that is interfering with normal function or poor oxygen absorption by the circulatory system.

The Air We Breathe & Exercising in It

Everyone breathes air, it is a fact of life. But have you ever thought about how the air quality affects your body, how it affects your healthy, active lifestyle outdoors?

Air pollution is a part of daily living in China as well as throughout the world. The air we all breathe in is composed of different gases such as oxygen, carbon dioxide, and nitrogen. Normally we are all fine with the air that we breathe with the exception to those who may have asthma or another respiratory ailment. In urban areas the aspects of daily living can have a huge impact on the air quality. Think of an industrial area or an area with large amounts of traffic daily. These areas are where air pollution is more noticeable because there are car exhaust fumes and factory fumes entering the air. In China the two cities with the best air quality are Shanghai and Guangzhou (close to the coast and have regular rainfall).

Two of the main components of air pollution are colorless, odorless gases: ozone and carbon monoxide. These two gases create smog when combined with the atmosphere. Both gases are emitted by factories that use coal for fuel, exhaust fumes from vehicles, and the combustion of fuels. Ozone levels in the atmosphere are highest in the afternoon; especially on sunny, windless days.


How does Air Pollution effect the body when exercising outdoors?

There are definitely days when you can notice the air quality is poor, you may even be able to see it when looking outside (smog). On these days it is advisable to adjust your training plan to train either in your home or a fitness facility.

Exercising outdoors on poor air quality days can have a negative impact on your body and training. When you reach a submaximal exercise level (power output= 100W or a respiratory rate greater than 35 breaths/minute) your body will switch from nose breathing to mouth breathing. Breathing through your nose allows the body to filter out some of the harmful particles in the air due to nose hair and mucous.

Short-term exposure to air pollution will alter your body’s lung and cardiovascular function. If you are training for a race or competition this could alter your VO2max level and cause you to reach your ventilatory threshold quicker than normal, which can decrease your training time or overall stamina for competition. Breathing patterns are altered when exposed to air pollution as it is a respiratory irritant. For those with asthma or diabetes the effects can be intensified or felt sooner in comparison to someone who doesn’t.

Chronic exposure to air pollution can increase your heart rate, which can decrease your athletic performance, stamina, and even athletic career.

Health Problems That Can Occur

Air pollution damages the air way and causes bronchoconstriction (narrowing of the airway. This in return makes the heart and lungs work harder in order to get oxygenated blood to all the tissues of the body. When you are exercising you may feel tired sooner.
Other health problems include:
– Increased risk of asthma and respiratory conditions
– Increased risk of cardiovascular disease
– Angina attacks
– Increased risk of lung cancer

Tips for Exercising in Polluted Areas:

– Monitor the Air Quality Index (AQI) (see photo below if you are unfamiliar)
– Avoid training near industrial areas
– Avoid training in the afternoon or rush hour
– Train early in the morning when the AQI is low
– Decrease training intensity and duration when the AQI is high
– Train inside
– Antioxidant supplementation
– Take steps to decrease the risk for cardiovascular disease
– Use anti-asthmatic medication as prescribed
– Consult with your physician with any concerns