The Navy SEAL Physical Fitness Guide 19
Repetition Running
This method is similar to interval training, but unlike interval training, the length of
the intervals are longer and usually range from 0.5 to 2.0 miles. Recovery between intervals
lasts until the heart rate is under 120 beats per minute, or within 60% of your estimated Max
HR.
Conditioning and Deconditioning
Conditioning and deconditioning, also known as training and detraining, are
responsible for gains and losses, respectively, in fitness levels. Whereas conditioning is a
gradual process and may take six or more weeks to see specific effects, deconditioning
occurs relatively quickly. Some of the various metabolic and cardiorespiratory effects of
conditioning are presented in Table 1-4.
Effects of deconditioning will be noticed within one to four weeks. Deconditioning
reverses the positive metabolic, cardiac, respiratory and muscle enzyme effects that result
from conditioning. Some major effects of deconditioning include:
Table 1-4. Various Effects of Physical Conditioning
Metabolic Changes
Cardiorespiratory
Changes
⇑ levels of ATP, CP, glycogen ⇑ in blood volume⇑ levels of anaerobic enzymes ⇓ heart rate at given workload⇑ capacity to tolerate blood lactate ⇑ stroke volume⇑ levels of oxygen within muscle ⇑ ability to take oxygen from blood⇑ levels of aerobic enzymes improvement in blood pressure⇑ capacity to use fat as fuel ⇑ ability to handle heat load