The oxygen transport system within our body is complex, a network of blood vessels that flow throughout our body, with the driving force stemming from our heart. The heart is known as the ‘central transport system’ whilst the veins, arteries and capillaries are the ‘peripheral transport systems’, and it is the unified job of these two systems that allow oxygen delivery to your muscles. The more oxygen your body can deliver the better, and the term that quantifies your body’s ability to deliver oxygen to a working muscle is known as the VO2 Max. VO2 Max is described by Bompa (1999) as the maximum amount of oxygen (ml) used in one minute per kg body weight. According to French and Long (2012), an average males VO2 Max is 3.5litres/minute and 2.7litres/minute for females.
Oxygen as a limiting factor in exercise
The delivery of oxygen to the muscle is fundamental for energy metabolism and the utilisation of Adenosine Triphosphate (ATP), minimising the accumulation of waste products, and maintaining a desirable blood pH. If Oxygen delivery is impaired then training becomes ‘anaerobic’ meaning energy is generated in the absence of oxygen. The problem with anaerobic exercise in endurance events is that the energy systems used in the absence of oxygen are not as sustainable as the ones used when oxygen is present, so consequently the anaerobic energy system (lactic acid system) means the body uses lactic acid as an energy source. If lactic acid is allowed to accumulate in the blood stream, and the rate that it enters the blood exceeds the rate of removal… the pH of the blood decreases, making it more acidic. The breakdown of lactic acid results in the release of Hydrogen ions, or protons, and it’s these little blighters that result in elevated blood acidity, increased fatigue, and eventually…diminished performance.
Maximising oxygen delivery
VO2 Max or Max VO2 capacity is a key factor in oxygen delivery, and thus exercise capacity, making it a major focal point of any distance runner, cyclist, triathlete or endurance athlete’s fitness regime. VO2 Max training is designed to enhance the oxygen transport systems ability to deliver oxygen to the muscle.
Training VO2 Max
In order to develop your VO2 Max, aim to exercise at around 80-90% intensity for a 3-5 minute duration or longer. Inherently ones heart rate will be high at this intensity, and it is expected that the heart rate should be at or around maximum, or within 10 beats per minute of maximum heart rate to invoke any improvement (unless the individual has an underlying medical condition). VO2 Max can also be trained through shorter bouts of exercise lasting around 30-60secs, but emphasis must be on minimising the duration of rest periods (no more than 10 – 60secs) for maximal effect. French and Long (2012) have explained that optimal training intensities involve elevating the heart rate to 65-85% of its maximum for at least 20mins, at least 3-5 times a week.
Supplements supporting the development of VO2 Max
One of the key talking points at the recent Sport Nutrition Conference in Paris was the effect of caffeine on exercise performance, particularly High Intensity Interval Training aka HIIT. Caffeine has a stimulatory effect on the central nervous system (brain and nerves) and can help to induce acute (short term) training adaptations allowing you to train more intensely, key factors in the development of VO2 Max. Approx 3mg per kg body weight is a good gauge for caffeine ingestion, so approx 210mg consumed approx 30-40mins prior to exercise is ideal for an average 70kg male. After ingestion, caffeine is absorbed into the blood and other body tissues within 5 minutes, and peak concentration is reached in about half an hour, with half-life (time for half the dose to be used up) is approximately 4 hours.
As mentioned earlier, ATP is one of the key metabolites for energy production in the body, therefore through promoting the resynthesis of ATP we can increase our capacity to train. Creatine is a key component of the Phosphocreatine energy system, and is therefore a useful supplement for power endurance activities such as plyometric jumps, sprints and intermittent sprinting, and indeed HIIT.
Sodium Bicarbonate, or similar alkalising agents such as Udo’s Choice Beyond Greens and PHD Nutrition Greens pH 7 may exert both acute (short term) and chronic (long term) training adaptations through its ability to keep the body in an alkaline state. Again, as mentioned above, our bodies become more acidic as we become depleted of oxygen, so pre-alkalising the body prior to exercise may help to stave off fatigue both in the short and long term.
Bompa, T, (1999). Periodization. Theory and Methodology of Training. 4th Ed. Maximum Oxygen Consumption Training. York : Human Kinetics
French & Long (2012) Retrieved 7th Aug, 2013, from http://www.brianmac.co.uk/vo2max.htm . Brian Mac Sports Coach. VO2 Max.
Tipton, K, D & Luc van Loon, (2013). Nutritional Coaching Strategy to Modulate Training Efficiency. Sodium Bicarbonate. Karger.