Get your second wind by perfecting the diastolic stepping technique. Diastolic stepping is when an individual's heart rhythm is in sync with their cadence. Essentially, this makes the body more efficient during those long distance runs and rides.

For more information, read the nerdy bits below.

During dynamic exercise, blood flow is produced by two opposing pumps. The heart provides the pressure head for blood flow to skeletal muscle and contracting skeletal muscle pumps blood back to the heart. Synergy between these two pumps could provide cardio-metabolic efficiencies that are beneficial for endurance exercise performance. Maximal benefit is achieved when cardiac and skeletal muscle contractions rates (bpm) are equal. During the rhythmic locomotion of running and cycling, natural synchronization often occurs between heart rate (HR) and step rate (cadence).

In fact, often there is an observed constant 1:1 ratio between HR and cadence (bpm) in competitive distance runners. This phenomenon has been traditionally called cardiac-locomotor coupling (CLC), and in more contemporary literature: diastolic stepping. 

If cardiac and locomotor phase timing are optimally coordinated, hemodynamic efficiency and cardiovascular function may be improved, positively affecting endurance performance.

Timing foot strikes and subsequent skeletal muscle contraction to occur consistently with cardiac diastole (i.e. between cardiac contractions), cardiac afterload may be reduced, cardiac preload may be increased, and skeletal muscle perfusion is promoted. 

Importantly, very small changes in physiological outcomes (such as diastolic stepping) can have quite large performance effects in distance running events.

References:

1.  Constantini K, et al, "Synchronizing gait with cardiac cycle phase alters heart rate response during running', MSSE 2018. 
2. O'Rourke M et al, "Improved cardiovascular performance with optimal entrainment between heart rate and step rate during running in humans', Coron Artery Dis, 1992.
3. Kirby RL et al, "Coupling of cardiac and locomotor rhythms", J Appl Physiol 1989.

This data was collected from an athlete during a road cycling workout using the W2ND android app.

Road cyclist cadence while standing is equal to 60 bpm, actual accelerometer data from W2ND device worn on the chest.

Road cyclist cadence while seated is equal to 90 bpm, actual accelerometer data from W2ND device worn on the chest.