Appendix I—The Fatigue Index
This simple test has proven effective in detecting the early stages of overtraining in wildland firefighters. It is an inexpensive but accurate way to judge when a firefighter is accumulating fatigue. The results correlate closely with immune function: when the fatigue index goes up, immune function declines. All you need to conduct the test is a sturdy 8- inch bench (or bottom stair step) and a stop watch. A heart rate monitor helps, but is not required. You can teach wildland firefighters to take the test in the morning. The resting, exercise, and recovery heart rates are summed to provide a fatigue index. After a baseline is established, subsequent tests can gauge the extent of fatigue. Large increases in the fatigue index suggest the need for additional rest or a break from hard training (table I.1).
During a 3-week extended duty cycle, a firefighter chose to ignore the signs of fatigue appearing at day 8. By day 12, he had developed a serious cold and sore throat and was unable to work for the next 2 weeks.
The Fatigue Test Procedure-After rising in the morning but before breakfast or stimulants (tea or coffee):
- Sit quietly for 3 to 5 minutes
until your heart rate is stable.
You can read the paper during
this time.
- Take your resting heart rate at
the wrist for 10 seconds, then
multiply the number of beats
by 6 to get the rate per
minute.
- Start the stop watch and
begin stepping (up with one
foot then the other, then down
with the first foot and then
the other-the entire sequence
of stepping up and
down should take 2 seconds
and be repeated 30 times in 1
minute).
- After 1 minute of stepping,
stop and take the postexercise
heart rate while standing. Sit
down immediately afterward.
- Relax. At 30 seconds after
exercise, take your heart rate
(10 seconds x 6 = beats per
minute).
- At 60 seconds after exercise, take the final heart rate.
To calculate the fatigue index, sum all heart rates (resting, postexercise, 30-second recovery, and 60-second recovery). The total is the fatigue index. The index is unique for each individual and should be compared to the individual's average index for several days during a rested period. Use table I.1 to evaluate the index.
| Increase in Fitness Index | Risk of overtraining |
|---|---|
| 0 to 20 above normal | Not generally a concern unless sustained |
| 20 to 30 above normal | Slightly increased (Avoid hard training) |
| 30 to 45 above normal | Increased risk (Suggest easy training only) |
| More than 45 above normal | High risk (Suggest no training) |
| Reprinted, with permission, from B.J. Sharkey and S.E. Gaskill, 2006,
Sports physiology for coaches. (Champaign, IL: Human Kinetics), 238. |
|
Avoiding overtraining is as much an art as a science, requiring careful observation of fatigue symptoms, good communication, and the willingness to rest-the only effective treatment for overtraining or overwork. Mild cases may improve with reduced workload and more rest. More serious cases demand time off or even bed rest. Because the immune system is depressed, an overworked wildland firefighter is more likely to contract an upper respiratory tract infection. Remember, training should be approached as a gentle pastime. Make haste slowly and you will eventually reach your goals.
