Tolerance intervals involve high-intensity training with relatively short intervals. The high intensity challenges the anaerobic energy systems, and with moderate rest lengths, the aerobic systems also work hard.
Unfamiliar with aerobic and anaerobic concepts? Learn more here.
A demanding type of interval
These intervals are often used by 5000m elite runners in the final phase of training before competitions. It's a very demanding form of interval training and likely not advisable year-round.
The name “tolerance intervals” comes from the demand to “tolerate” high levels of fatigue substances in the body. With high intensity and moderate rest, each interval accumulates fatigue substances that aren't fully cleared before the next interval.
Short and intense
The typical length of these intervals is around 150-600m, at a pace near 800-1500m speed. Essentially, almost sprinting! Rest lengths are longer than the interval length – often 1:2, e.g., 25 seconds interval with 50 seconds rest.
For this type of interval, it can be useful to discuss both rest and set rest. This means performing a certain number of intervals with a given rest (a set), then taking a set rest before starting the next set.
An example could be 2 x (8 x 25 sec) – 2 sets of 8 x 25-second intervals with 50 seconds rest and a set rest of 2 minutes.
In the above, you should:
- Set 1: Run 8 x 25 seconds with 50 seconds rest between each interval.
- Take a 2-minute set rest.
- Set 2: Run 8 x 25 seconds with 50 seconds rest.
Examples of tolerance intervals
- 16 x 30 seconds intervals with 1-minute rest
- 2 x (10 x 400m) with 2 minutes rest and a 5-minute set rest
- 20 x 150m with 150m walk/slow jog
