VO₂Max represents the synchrony of your cardiovascular system, your lungs and your muscles in delivering oxygen to muscle cells, leading to more energy. VO₂Max is defined as the maximum rate of oxygen that can be delivered to and used by the working muscles, aka aerobic capacity. It is considered a marker of cardiorespiratory fitness (CRF) and the level of physical preparedness of an athlete. Simply put, VO₂Max reflects the entire oxygen transport and response systems.

VO₂Max reflects the entire oxygen transport system – the lungs, cardiovascular, and active muscles- which transport and utilize the oxygen in the blood stream as you train. It is the functional capacity of the lungs, the pumping capacity of the heart, the ability of the blood and vascular system to deliver oxygen to the working muscles, and the ability of these muscles to absorb and use oxygen that all work together to produce a VO₂Max level.

Tip: Not recognized, but also part of the system are your brain, your diaphragm, your red blood cells, and other organs, as well as your gut bacteria - remember rather than ‘you are what you eat’ it is really that ‘you are what you liberate and absorb from your gut’. It’s a busy system.

VO₂Max is measured in milliliters of oxygen used in one minute per kilogram of body weight (mL/kg/min). The more oxygen your body absorbs per minute, the higher your VO₂Max, and the more fit a person is (Green & Askew, 1985; Poole & Jones, 1985; Burtscher et al, 2019; Valenzuela et al, 2020). It is based on the premise that the more oxygen athletes consume during high-level exercise, the more the body will generate energy in the cells.

VO₂Max is typically evaluated in laboratories on treadmills, cycling ergometers, or rowing ergometers by gradually increasing intensity over some time of more than 5 minutes (Beltz et al, 2016).

VO₂Max values can vary greatly between individuals, with untrained individuals typically having a range of 25-45 ml/kg/min while elite endurance athletes have values in the 80s or even 90s. Males tend to have higher values than females. After 30 years of age, VO₂Max progressively decreases with age at a rate of about 10% per decade (Jansson & Kaijser, 1987; Simon et al, 1986; Levine, 2008), though appropriate training can slow the pace of decline (Haugen et al, 2018; Rønnestad et al, 1985; Weibel & Hoppeler, 200).

Given that VO₂Max represents three major organ systems, anything that impacts any or all of those systems would lower your scores. For example, aging can impact heart functioning, leading to a decline in maximal heart rate and in VO₂Max levels. Cardiovascular disease, such as the stiffening of arteries, or heart disease, can negatively affect blood flow and oxygen delivery to skeletal muscles (Poole et al, 2002; Burtscher et al, 2022).

Respiratory infections, such as molds, yeasts, bacteria, and viruses, or any disturbance in lung function, such as smoking can and will impact your cardiorespiratory system. Also, poor range of motion of the diaphragm and the ribs will have a negative impact on lung capacity.

A poor diet, without adequate amounts of healthy fats, protein and carbs mean that your muscles would not have the quality substrates available to metabolize during exercise and during recovery. It is your intake of healthy food that is stored in your muscles and fat that is called upon during exercise.

As an example, vitamin K1 (Phylloquinone) is obtained from green leafy vegetables and vitamin K2 (Menaquinone) is obtained from some meats, and fermented foods. If your diet does not include sufficient amounts of those nutrients, then you may lack the K needed to activate important proteins in lungs, muscles or your cardiovascular system, leading to impairments in your performance.

While performance impairments can be a short-term issue, insufficiency or deficiencies in your diet over time, can lead to long-term health issues, and may set you up for chronic health issues as you get older. The Triage Theory refers to the belief that when the availability of a micronutrient is inadequate, nature ensures that functions required for short-term survival are protected at the expense of functions, whose lack has longer-term consequences, such as diseases associated with aging (McCann & Ames, 2009).

Any intervention that mitigates the effect of aging, such as vitamin K is important.

Thus, it becomes clear that any increase in VO₂Max represents an increase in health and fitness. It is very important to realize that physical training with proper mechanics, as well as the micronutrients that support the underlying biochemical and molecular mechanisms of your body can lead to increases in VO₂Max.

Vitamin K
There is one direct study of the impact of vitamin K on VO₂Max. In a recent randomized controlled trial, MK7 was given to subjects during an 8- week period, while they maintained their typical exercise habits. They found that MK7 intake was associated with a 12% increase in maximal cardiac output, using a graded cycle ergometer test. It showed a powerful effect of MK7 on heart output during exercise in active athletes. This was the first study to report potential of vitamin K in active individuals.

Cardiac output was defined as the maximum amount of blood (and therefore oxygen) that the heart can pump around the body each minute. This increase translates to an increase in the maximum amount of blood and oxygen available to exercising muscles, which should improve endurance. Research on elite runners and cyclists have confirmed that high cardiac outputs are associated with high levels of endurance performance (McFarlin et al, 2017).

Vitamin D
Studies on the interaction between aerobic power (determined by VO₂Max) and vitamin D in athletes are contradictory (Eslami et al, 2017; Wyatt et al, 2024). There are observational studies simply looking at the existing levels of vitamin D and VO₂Max without supplementation. Some found that vitamin D levels are associated significantly correlated with VO₂Max (Ardestani et al, 2011; Koundourakis et al, 2014; Forney et al, 2014, Marawan et al, 2019; Most et al, 2021), while other studies have found no association (Książek et al, 2019).

There are supplementation studies, also with mixed results. Several studies have found that supplementing with vitamin D did raise VO₂Max scores. Lightweight rowers with sufficiently high vitamin D levels (> 30 ng/ml) were observed during an eight-week training phase where either 6,000 units of vitamin D or placebo were administered daily. Those who received the Vitamin D showed a significant increase in VO2Max (12.1% compared to 10.3%) and an increase in vitamin D levels by around 400% (Jastrzębska et al, 2014). Youth soccer players received either vitamin D (5,000 IU/day) or a placebo during eight weeks of intensive training. In the supplementation group, vitamin D concentration increased by 119% and VO₂Max by 20%; in the placebo group, vitamin D concentration decreased by 8.4% and VO₂Max increased by 13%, suggesting that vitamin D supplementation may have a beneficial, though moderate, impact on aerobic capacity in youth soccer players (Jastrzębska et al, 2018).

Active college students, who were vitamin D deficient (< 20 ng/mL), supplemented with 6000 IU of vitamin D daily for eight weeks, and showed a significant improvement in maximal aerobic power and improved physical capacity (Kujach et al, 2020). Polish soccer players undergoing high intensity training, were given 20,000 IU of vitamin D twice a week for eight weeks. When compared to a group who received a placebo, they showed a significant improvement in VO₂Max (Brzeziański et al, 2022).

Other research showed no effect between supplementation and VO₂Max. A study of Gaelic football players showed that 72% had inadequate levels of vitamin D. The daily intake of 3,000 IU vitamin D3 for 12 weeks only corrected the vitamin D deficit but had no meaningful effect on VO₂Max. The authors questioned whether it is the supraphysiological doses of vitamin D3, greater than 3000 Ius would have a beneficial effect (Todd et al, 2017). Vitamin D supplementation did not improve muscle strength and cardiorespiratory endurance in 90 military recruits with a vitamin D deficiency. 1 group received cholecalciferol 60,000 ius every fortnight for twelve weeks but there was no significant change in muscle strength or VO₂Max at the end of training (Menon et al, 2020). Young men engaged in resistance training who were vitamin D deficient, were given 8000 IU of vitamin D daily for 12 weeks. Serum Vit-D concentrations increased 3.9-fold (p < 0.001) in the Vitamin D group while no changes occurred in the placebo group. Baseline VO₂Max did not differ in the two groups and remained unchanged during the intervention, however inflammatory status improved in the group that received vitamin D (Savolainen et al, 2022).

Tip: It takes time for your body to assimilate vitamin D, so determine if you may need it and plan accordingly to add it to your training schedule.

For elite athletes, improving performance by 2-3 percent is the difference between a podium finish and being in the middle of the pack. The research indicates that supplementing with vitamin K has led to a significant increase in VO₂Max, and while the studies with vitamin D have produced mixed results, there are a number of studies showing that vitamin D often leads to improved levels of VO₂Max levels in only a couple months.

Tip: For incremental performance improvement there is a high probability that you need both vitamin K and vitamin D.

References

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