Determining the optimal rest period between intervals is key for maximizing the benefits of interval training. The right rest period allows your body to briefly recover before the next intense effort, leading to greater gains in endurance, speed, and power. However, there is no definitive answer on the perfect rest time, as it depends on your training goals, the length and intensity of the intervals, and your current fitness level. Typically, more rest is needed for high-intensity sprints while shorter rests are common for longer, submaximal intervals. Here’s an in-depth look at how to find the ideal rest time for your intervals.
Why Rest Time Matters
Rest periods serve several important purposes during interval training:
- Allow partial recovery – Short rest periods of 30 seconds up to a few minutes give your muscles and cardiovascular system a chance to bounce back before the next interval effort. This allows you to repeat high-intensity work multiple times in a session.
- Clear metabolic byproducts – Intense interval efforts cause a buildup of lactate and other metabolites linked to fatigue. A short rest period helps clear these byproducts so they don’t hinder performance in the next interval.
- Replenish energy – Brief recovery periods enable your body to tap into stored ATP, creatine phosphate, and glycogen to restore muscle and liver fuel sources for the upcoming interval.
- Maintain intensity – Optimal rest times ensure you can complete each interval at the desired intensity and speed. Too little rest may cause your pace to drop while too much rest can allow you to fully recover and reduce the overall training stimulus.
The ideal rest time gives you just enough recovery to repeat the interval at the right intensity but not so much that your body is fully refreshed. This keeps sessions demanding and effective at building endurance and speed.
Factors That Determine Optimal Rest Time
Several key variables play a role in finding the right rest period length for your intervals:
Interval Duration
Longer interval periods require more rest time for full recovery. For example, 3-5 minute intervals typically need 2-3 minutes rest while 30-60 second sprints may only require 30-90 seconds rest.
Interval Intensity
Higher intensity intervals demand longer rest periods. You’ll need more recovery after fast sprints compared to submaximal tempo runs.
Energy System Targeted
Aerobic interval sessions can be repeated with shorter rest while intervals focused on power and speed require more recovery between efforts.
Overall Interval Volume
Workouts with higher total interval volume (more repetitions x time per interval) necessitate longer rest periods to facilitate completion.
Fitness Level
Better conditioned athletes can repeat intervals with less rest whereas lower fit individuals need longer recovery periods.
Goals of the Session
Rest times can be adjusted to elicit specific adaptations. Shorter rests push aerobic development while more recovery emphasizes speed and power gains.
General Rest Time Recommendations
Though optimal rest depends on your specific workout design and fitness, here are general guidelines on recovery period lengths:
For Long Intervals:
- 3-5 minutes – Rest 1:1 with work period. If intervals are 3 minutes long, take 3 minutes rest.
- 2 minutes – Rest 1:1 to 1:0.5 with work period. So 2 minute intervals would have 2 to 1 minutes rest.
- 1 minute – Take 30-90 seconds rest.
For Short Speed Intervals:
- 30 seconds – Rest 30-60 seconds
- 15-20 seconds – Rest 15-30 seconds
- 10 seconds or less – Rest 10-20 seconds
Adjusting Rest Time to Meet Training Goals
You can manipulate rest interval length to target specific physiological adaptations:
Boost Speed and Power
Allow near complete recovery with a work to rest ratio of 1:2 up to 1:5 for intervals focused on speed development. The long rest enables repeated fast efforts.
Build Muscular Endurance
Use slightly shorter recovery periods of 1:1.5 or 1:1 work to rest ratios on moderate to hard muscular endurance intervals.
Improve Lactate Threshold
Utilize work to rest ratios around 1:1 for longer tempo intervals just below lactate threshold pace.
Increase VO2 Max
Keep rest periods short at 1:1 or slightly less work to rest ratio to maximize aerobic gains from VO2 max intervals.
Determining Your Ideal Rest Time
While the guidelines above provide a helpful starting point, you’ll need to fine-tune rest intervals based on your individual response:
Self Assessment During Intervals
Gauge how you feel during sessions. If you struggle to complete later intervals with good form and speed, extend the rest time. If you feel fully recovered, try shortening rest periods.
Heart Rate Recovery
Monitor how quickly your heart rate drops during the rest interval. Reaching approximately 120 bpm or 50-60% of maximum HR signals adequate recovery before the next work interval.
Interval Pace & Power
If your speed or power output consistently declines during intervals, you need more rest time in between. Consistent repeatability indicates appropriate recovery periods.
Listen to Your Body
Your subjective sense of exertion matters too. If you feel drained or are unable to push yourself during intervals, err on the side of more rest between hard efforts.
Sample Interval Rest Periods
Here are examples of appropriate rest times for various interval workouts:
VO2 Max Intervals
- 3 x 1000m @ 5K pace – 90 sec rest
- 8 x 400m @ mile pace – 60 sec rest
Lactate Threshold Intervals
- 3 x 3 min @ LT pace – 1.5 min rest
- 5 x 1000m @ 10K pace – 2 min rest
Speed Intervals
- 10 x 100m sprints – 20 sec rest
- 6 x 40 yd dashes – 30 sec rest
Using Active Rest to Enhance Interval Workouts
Active recovery during rest intervals can enhance interval training adaptations:
- Keeps heart rate elevated to sustain cardiovascular workload
- Enhances lactate clearance
- Limits reductions in muscle temperature
- Maintains feel for pace
Some examples of active rest include light jogging, cycling easily, or marching in place. Keep effort under 70% max heart rate. Walking can work for beginners.
Final Recommendations
Optimizing interval rest time takes some trial and error but can pay big dividends in performance. While there are general guidelines based on the intensity and duration of work intervals, stay flexible based on your own response. Extend rest when needed to maintain workout quality and shorten as fitness improves. Lastly, recognize when to switch up your interval format entirely to keep challenging your body in new ways.
Conclusion
Finding the right rest interval duration is crucial for maximizing the benefits of interval training across different disciplines. Though general recommendations exist based on the length and intensity of work intervals, your individual fitness level also plays a key role. The ideal rest time enables you to repeat high-quality efforts consistently throughout a workout. Adjust and monitor your rest periods based on subjective recovery, heart rate response, and ability to sustain target pace or power. Optimized rest interval length will ensure you train intensely and effectively to boost your speed, endurance and power.
