Hypoxic Endurance Exercise Performance benefits from IMT

This new study (2019) looks into whether chronic IMT improves hypoxic endurance exercise performance.

Endurance exercise performance

The study, in the International Journal of Sports Physiology and Performance, is using a cycling time trial to measure endurance exercise performance. Endurance exercise is typically performed at submaximal intensity. The purpose of this is to estimate VO2max, or ‘aerobic fitness’. The measurement VO2max is the maximum amount of oxygen a person will consume during intense exercise. In fact, cycling time trials offer the ideal exercise to increase both heart rate and breathing. Similarly, so do running and swimming.

What is IMT?

IMT is a form of resistance training for the breathing muscles. The term IMT stands for inspiratory muscle training. The inspiratory muscles, the breathing muscles, are the ones that draw air into the lungs. The main inspiratory muscle is the diaphragm. Like any other group of muscles, the inspiratory muscles benefit from training too. Inspiratory muscle training, such as with POWERbreathe, provides the stimulus for that training. Following IMT, the breathing muscles adapt and become stronger after only a few weeks. This results in exercise feeling easier and an improvement therefore in performance.

Why IMT?

Although breathing comes naturally, some of the time it can feel like an effort. This may be due to the demand endurance exercise places on breathing. It may be due to a respiratory issue. Either way, it’s not uncommon for the respiratory muscles to fatigue, just like any other muscle.

If the respiratory muscles are weak from disease or exercise is overloading them, breathing demand will not be met. As a result, breathing will start to feel shallow and rapid. Sustaining this type of breathing is impossible. Furthermore, the more rapid the breathing, the more oxygen they require and the more carbon dioxide they produce. Consequently, oxygen is re-directed from the skeletal muscles, such as arms or legs, to the breathing muscles, where it is most needed. This results in fatigue of the skeletal muscles.

Inspiratory muscle training helps the body meet the needs of both the respiratory muscles and the skeletal muscles by improving their strength and stamina. The way IMT achieves this is by providing a resistance to breathe in against. POWERbreathe IMT is just like a ‘dumbbell for your diaphragm’.

Study results

Data from this recent study suggest that,

“performing 6 weeks of inspiratory muscle training may benefit hypoxic endurance exercise performance lasting 30-40 minutes.”

Influence of IMT on Cycling Performance at altitude

This study, Influence of IMT on Ventilatory Efficiency & Cycling Performance in Normoxia and Hypoxia, is published in Frontiers in Physiology. The aim of the study is to analyse the influence of inspiratory muscle training (IMT) on ventilatory efficiency in normoxia and hypoxia. It also investigates the relationship between ventilatory efficiency and cycling performance.

The point of the study

The premise of the study is that IMT improves ventilatory efficiency in normoxia and hypoxia. It also reduces the metabolic demands of the respiratory muscles in both conditions. The study also hypothesizes that improvements in submaximal cycling performance can be linked to improvements in ventilatory efficiency in normoxia and hypoxia.

Study method

The study assigns participants, at random, to either a control group or an inspiratory muscle training (IMT) group. The IMT group were to complete 30 inhalations twice a day using the POWERbreathe K3. They were to do this 5 days a week for 6 weeks. Researchers set the POWERbreathe K3 to 50% of each participant’s Pimax (maximal inspiratory mouth pressure). By contrast, the control group did not perform any IMT.

To determine Pimax participants had to inspire through the K3 as quickly as possible. And in order to achieve a stable measurement they were perform this a few times.

Conclusions for training at altitude

The study suggests a possible positive effect of IMT on cycling time trial performance in both normoxic and hypoxic conditions. It also shows that hypoxia has a negative effect on ventilatory efficiency. It furthermore shows that IMT may reduce this effect.

Additionally the authors report that these findings may have relevance for athletes planning to train at a high altitude, or compete at high altitude.

Finally, the study suggests that Inspiratory Muscle Training before a competition at altitude might be a successful method to improve performance.

Inspiratory Muscle Training, Altitude, and Arterial Oxygen Desaturation: A Preliminary Investigation

“Specific inspiratory muscle training (IMT) has been shown to significantly attenuate the fall in arterial oxygen saturation (SpO2) during exhaustive exercise while breathing a hypoxic gas mixture of 14% oxygen. The aim of this study was to assess the impact of IMT on resting oxygen saturation over a range of altitudes in healthy individuals.”

Conclusion:

“IMT can attenuate the fall in resting oxygen saturation, but only at altitudes of 4880m and above. Conversely, IMT had no effect on resting levels of dyspnea as measured by the Borg Score.”

Read Inspiratory Muscle Training, Altitude, and Arterial Oxygen Desaturation: A Preliminary Investigation >

Effects Of IMT On Exercise Responses In Normoxia And Hypoxia

“The purpose of this study was to determine the effects of inspiratory muscle training (IMT) on exercise in hypoxia (H) and normoxia (N)”.

Conclusion:

“Data suggests that IMT significantly improves structural and functional physiologic measures in hypoxic exercise.”

Read Effects of inspiratory muscle training on exercise responses in normoxia and hypoxia >