Breath Tools: A Synthesis of Evidence-Based Breathing Strategies to Enhance Human Running

Abstract

Running is among the most popular sporting hobbies and often chosen specifically for intrinsic psychological benefits. However, up to 40% of runners may experience exercise-induced dyspnoea as a result of cascading physiological phenomena, possibly causing negative psychological states or barriers to participation. Breathing techniques such as slow, deep breathing have proven benefits at rest, but it is unclear if they can be used during exercise to address respiratory limitations or improve performance. While direct experimental evidence is limited, diverse findings from exercise physiology and sports science combined with anecdotal knowledge from Yoga, meditation, and breathwork suggest that many aspects of breathing could be improved via purposeful strategies. Hence, we sought to synthesize these disparate sources to create a new theoretical framework called "Breath Tools" proposing breathing strategies for use during running to improve tolerance, performance, and lower barriers to long-term enjoyment.

Keywords: breathing pattern; coupling; respiration; running; strategies; techniques; ventilation.

Figure 1

Exercise breathing pattern changes during increasing exercise intensity. Note the nonlinear increase in breathing rate and unequal partitioning of EILV and EELV as intensity increases. TLC, total lung capacity; LOV, lung operating volume; VC, vital capacity; RV, residual volume; EILV, end-inspiratory lung volume; EELV, end-expiratory lung volume; and V_T, tidal volume.

Figure 2

The “respiratory limiting cycle” cascade of phenomena leading to respiration limiting exercise performance and enjoyment. Increasing exercise intensity interacts with pre-existing individual constraints, causing an accumulation of respiratory phenomena that ultimately harm performance and cause dyspnoea. Dashed arrows indicate mechanisms specific to high relative exercise intensities. Adapted with permission from BradCliff® and Bradley and Clifton-Smith (2009).

Figure 3

Dynamic hyperinflation occurs when accumulated breath stacking progressively increases lung operating volume. When lung operating volume approaches total lung capacity, lung stiffness, and suboptimal diaphragm position increase the work of breathing (WOB) and dyspnoea. TLC, total lung capacity; LOV, lung operating volume; EILV, end-inspiratory lung volume; EELV, end-expiratory lung volume; and V_T, tidal volume.

Figure 4

Respiratory inductance plethysmography data from our lab showing normal breathing (dashed line) vs. “rate” breathing strategy (solid line). Note longer breath duration (horizontal) and related larger tidal volume (vertical) for each breath cycle.

Figure 5

Schematic showing the difference between upper-thoracic dominant breathing (A,C) vs. “deep” diaphragmatic breathing (B,D). (A) Upper-thoracic breathing elevates and expands the upper ribcage, visible in (C) respiratory inductance plethysmography measurements from our lab showing increased amplitude in thoracic vs. abdominal bands. (B) Deep breathing flattens the diaphragm against the inferior abdominal viscera, expanding the abdominal ribcage via pump- and bucket-handle mechanisms. Adapted from Isometric angle of diaphragm and ribcage by Chest Heart & Stroke Scotland and Stuart Brett, The University of Edinburgh 2018 CC BY-NC-SA; arrows added for emphasis.

Figure 6

Respiratory inductance plethysmography (RIP) data from our lab showing normal breathing (dashed line) vs. “active exhale” breathing strategy (solid line). Note that raw RIP data depict inductance, where signal increases (upward slope) correspond to the exhale phase. Observe the identical breath cycle time, but shorter relative inhale and longer exhale (smaller breath ratio) as well as lower average lung operating volume throughout the breath cycle (higher signal units indicating decreased sensor stretch).

Figure 7

Respiratory inductance plethysmography data from our lab showing locomotor-respiratory coupling (LRC). (A) Phase synchrogram and LRC ratio plotted during 8 min of running at an instructed LRC ratio 3:4 (steps per inhale:steps per exhale). Note the quantity of steps synchronized with inspiration vs. expiration. All relative phase shifted 90° for visibility. (B) Subsection of 10 s of raw RIP and hip-mounted accelerometer data while running at 3:4 LRC. Dotted lines added to emphasize step & flow reversal synchronization.

Figure 8

Respiratory inductance plethysmography data from our lab showing normal breathing with one approximate 10 s end-expiratory breath hold. Note the very long double exhale and brief diaphragm twitch.