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:
- Decrease in maximal aerobic capacity - Heart rate for a given exercise workload
is higher and the amount of blood pumped by the heart with each beat is reduced.
- More rapid build up of lactic acid during exercise which leads to earlier fatigue.
- Reduction in levels of key muscle enzymes which regulate the muscle’s ability
to generate energy from various sources.
- Reduced ability to store glycogen in muscle between workouts.
- Reduced breathing volume which will decrease the amount of oxygen being
taken to the exercising muscle.
- Decreased endurance capacity - time to fatigue is shortened.
- Decreased ability to dissipate body heat during exercise: the ability to exercise
in adverse environments, such as in the heat, is reduced due to all factors
mentioned above.
Retraining is necessary to reverse the performance reducing effects of
deconditioning. However, deconditioning can be prevented or minimized by
maintaining usual exercise intensity during endurance and strength workouts, when
the number or length of work outs is decreased. Aerobic capacity and decreased lactic
acid accumulation during exercise can be maintained by training at least two to three times
per week at your usual training intensity. Strength gains can be maintained by including one
to two strength training workouts sessions per week. Specific training methods for
maintaining fitness under deployed conditions and while overcoming an injury will be
discussed in other chapters (see the next).
Active Recovery
This type of recovery means that you continue to exercise at a low to moderate
(30% to 50% of your maximal heart rate) intensity for several minutes after your regular
workout. For example, walk for 5 to 10 minutes after completing a run. The benefits of
active recovery and additional information about this type of recovery are provided in