Spiroergometry testing (VO2 Max) and resting energy expenditure testing (REE)
If you have ever wondered how optimally your body truly functions, how much energy it can produce, and how prepared it is for a long and healthy life – the answer is not only found in the mirror, but deep within your physiology.
That is why, within our Longevity programs, we use spiroergometry testing (VO2 Max) and resting energy expenditure testing (REE) to gain a complete picture of your body, from peak performance to baseline energy consumption.
Spiroergometry testing (VO2 Max)
VO2 max represents the maximum volume of oxygen (V - volume, O2 - oxygen) that the body can transport and utilize during intense exercise. The higher your VO2 max, the more efficient your heart, lungs and muscles are - allowing you to produce more energy, recover faster, and sustain effort longer without fatigue. In medicine, it is a direct indicator of cardiorespiratory fitness and mitochondrial health.
Scientific research confirms that a high level of cardiorespiratory fitness (measured through VO2 max) is a stronger predictor of longevity than many traditional risk factors. Importantly, this is not just a test for athletes, it is a test of the vitality of your heart, lungs and mitochondria, the energy powerhouses of your cells.
We often focus only on body weight or appearance, but the true picture of health lies within the function of our heart and lungs. VO2 max (maximal oxygen uptake) is considered the gold standard for assessing cardiorespiratory fitness and one of the strongest predictors of longevity.
The test itself is safe and non-invasive (although it requires physical effort) and is conducted under professional supervision. The entire process takes approximately 30 to 45 minutes, including preparation.
What do we assess with VO2 Max testing at Sv. Katarina?
By precisely measuring gas exchange on a treadmill or stationary bike, we obtain data that scales and standard smart devices cannot provide:
- Optimal heart rate zones - we determine your individual training zones so you know exactly when you are building endurance and when you are overstraining your body.
- Fat-burning zones - we identify the exact intensity at which your body most efficiently uses fat as its primary fuel source.
- Fat oxidation capacity - we assess your metabolism’s real ability to utilize fat during exercise, which is crucial for weight management and metabolic health.
- Basal metabolic assessment - we estimate your resting energy expenditure, forming the basis for precise nutrition planning.
What does the testing process look like?
- Before the test, a heart rate monitor strap or ECG electrodes are placed to precisely track your heart activity during exertion. A key component is the ergospirometry mask, which covers your nose and mouth and is connected to highly precise sensors that analyze oxygen intake and carbon dioxide output in real time.
- The test is performed on a medical treadmill (standard for most individuals) or a cycle ergometer (ideal for cyclists or those with injuries preventing running), depending on your goals and condition.
- The test begins with light warm-up, followed by gradual increases in intensity each minute. The goal is to safely bring your body to its maximum capacity. Protocols can be further customized for professional athletes.
- The test continues until maximum exertion is reached (usually 8–12 minutes of active effort). Throughout the test, we monitor your heart rate and breathing gases. At peak exertion, we obtain the most valuable data: aerobic threshold, anaerobic threshold (when muscles begin to “burn” due to lactate accumulation), and VO2 max (your absolute cardiopulmonary capacity).
- After exercise, we continue monitoring recovery. These data show how quickly your heart and lungs return to baseline, which is another important health indicator.
Resting energy expenditure testing (REE)
REE represents the exact number of calories your body burns at complete rest to maintain vital functions such as heart activity, breathing, body temperature and brain function. In most individuals, REE accounts for 60% to 75% of total daily energy expenditure. This means that most calories are burned not during activity, but while sitting or sleeping.
Most people rely on general formulas, such as the Harris-Benedict equation, based on age, gender and weight. However, these formulas can be inaccurate by 20% to 30%, as they do not account for individual muscle mass, hormonal status, or genetic metabolic rate.
Who is REE testing for and what does it reveal?
This test is ideal for individuals who want to lose weight without the “yo-yo” effect and define a safe caloric deficit, as well as for those with metabolic disorders (such as insulin resistance or thyroid issues). It is also highly beneficial for athletes aiming to optimize energy intake and improve performance without losing muscle mass.
Precise REE measurement within our Longevity approach reveals:
- Whether your metabolism is slowed – often seen in individuals with a history of restrictive dieting.
- Exactly how much you should eat – providing a precise caloric intake below which you should not go for healthy weight loss.
- Diet effectiveness – allowing nutrition plans to be tailored to your actual energy expenditure rather than estimates.
What does REE testing look like?
During the test, you lie or sit comfortably for 15–20 minutes while wearing a mask. The device measures the exact ratio of inhaled oxygen (VO2) and exhaled carbon dioxide (VCO2). This gas exchange directly indicates how much “fuel” your cells are burning.
The respiratory quotient (RQ) reveals whether your body primarily uses fats or carbohydrates at rest. If your body relies mainly on sugars, this may indicate metabolic inflexibility, which can be improved through targeted exercise and nutrition.
Take control of your biological future and full potential. Book your appointment today.