How Many Days A Week Should I Run Intervals? Running Interval Guide

Interval workouts are the hidden gems of running training. They stand out as one of the most effective methods for rapidly boosting fitness levels and increasing strength. These workouts involve a rhythmic alternation between high-intensity sprints and periods of walking or jogging for recovery. Notably different from strides or fartleks, intervals demand focused sprinting over specific distances.

Ideally conducted on a track for precise speed measurement, intervals can be adapted for road running by accurately measuring distances. Because of their demanding nature, it’s often advisable to run intervals with fellow athletes to boost motivation and provide mutual support.

Interval training offers swift results compared to many other forms of speed training. It enhances running form, speed, endurance, and facilitates fat burning. However, a word of caution – moderation is key. It’s recommended to limit interval workouts to once or twice a week, allowing your body adequate time to recover from these high-intensity sessions.

But how do you actually run intervals? Let’s delve into the details of what intervals are and how to incorporate them into your training regimen.

What Are Intervals?

Interval workouts represent one of the most efficient methods for enhancing fitness and increasing strength rapidly. They involve alternating between high-intensity sprints and periods of walking or jogging for recovery. These intervals differ from strides or fartleks in that they require sprinting for specific distances.

While it is ideal to perform intervals on a track for precise measurement of your speed, it is possible to conduct them on the road as long as you accurately measure the distances. Due to their demanding nature, it is advisable to run intervals with other runners to boost motivation and provide support.

Interval training offers quicker results compared to most other forms of speed training. It not only enhances your running form, speed, and endurance but also aids in fat burning. However, it’s essential to avoid overdoing it – limiting interval workouts to once or twice a week is recommended to allow your body sufficient time to recover from the high-intensity sessions.

 

How Do You Run Intervals?

There are many different variations of intervals, so are able to customize them to suit your specific requirements. However, as a general guideline, shorter and swifter intervals (ranging from 200 to 400 meters) with brief recovery periods are optimal for 5K to 10K training. Conversely, for half-marathon or marathon training, it is advisable to opt for longer intervals (800 meters to one mile) accompanied by lengthier rest intervals.

The pace at which you complete the fast intervals hinges on factors like your fitness level, experience, and the target time for your upcoming race. During the rest intervals, it’s important to maintain a slow jogging or walking pace. Moreover, you should incorporate an extensive warm-up and cool-down routine on both ends of your interval training session to mitigate the risk of injury. More advanced runners might consider including five to ten minutes of drills such as skipping, high-knees, and butt kicks immediately after the warm-up.

Here’s an example of an interval workout:

1. Begin with a 20-minute warm-up.
2. Run 400 meters at a pace equivalent to your 5K race pace or slightly faster.
3. Jog leisurely for one minute to facilitate recovery.
4. Repeat steps two and three up to ten times (For beginners, it’s advisable to start with fewer repetitions).
5. Conclude with a 20-minute cool-down session.
6. Follow this with a stretching routine.

 

How Many Interval Sessions Should You Run Per Week?

Interval running workouts should not constitute the majority of your training regimen. In most established training approaches, interval running typically makes up no more than 20% of your overall training volume. Going beyond this 20% threshold can result in diminishing returns and the risk of overtraining. Excessive interval training, or excessively strenuous intervals performed for extended periods, may hinder specific aerobic adaptations, such as fat oxidation.

Several key factors should guide the planning of interval workouts:

1. Experience Level and Training History:
Interval workouts impose significant metabolic and biomechanical demands on the body. It’s crucial to have a solid aerobic foundation and adequate musculoskeletal adaptation before incorporating interval running. A general recommendation is for runners to spend at least 6-12 months engaged in easy runs before introducing interval training. Novice runners may require more recovery time after interval sessions, possibly necessitating complete rest days or cross-training on the day following an interval run. Experienced runners, on the other hand, may only need 48-72 hours between interval workouts, though their frequency may vary based on other factors.

2. Training Intensity Distribution:
Training intensity distribution refers to the breakdown of easy, moderate, and hard runs in a weekly training plan. Two common models are polarized and pyramidal. Polarized training typically involves around 80% easy, 0-5% moderate, and 15-20% hard efforts. This model frequently incorporates challenging interval workouts like VO2max intervals. In a pyramidal approach (common in endurance training), the distribution is approximately 80% easy, 15% moderate, and 5% hard. Pyramidal training emphasizes threshold and critical speed intervals while reducing the frequency of VO2max intervals.

3. Periodization:
Periodization involves manipulating training intensity and volume during different training phases to target specific adaptations. Research on world-class long-distance runners in 2022 showed variations in the periodization of hard-intensity intervals (above threshold) between marathoners and 1500m runners. Marathoners tend to spend more time in zone 3 (out of 3) in the early preparation phase, while 1500m runners do the opposite. For marathon preparation, shorter, faster intervals are recommended in the early training weeks. In the 8-10 weeks leading up to a marathon, intervals at moderate to moderately hard efforts (below critical speed) are advisable, with a focus on threshold intervals close to the race.

The reverse holds true for 5K races, which involve some anaerobic contribution. A 2022 study found that transitioning from pyramidal to polarized training before a race (incorporating higher-intensity intervals in the weeks before the race) led to significant improvements.

4. Individual Recovery Rate:
Factors like genetics, sleep quality, nutrition, and stress levels influence an individual’s recovery rate. Some runners may recover relatively quickly (within 48-72 hours) after an interval workout, while others may need more time.

5. Individual Strengths and Weaknesses:
Runners with a dominance of slow-twitch muscle fibers may benefit from more hard interval sessions. In contrast, fast-twitch runners preparing for long-distance races might require fewer intervals or a greater focus on intervals below critical speed to achieve desired aerobic adaptations.

 

Sample Interval Running Workouts

Interval running workouts can be customized by adjusting parameters such as intensity, the duration of recovery intervals, the number of repetitions, and the length of work intervals. Here’s a selection of some typical interval running sessions:

 

1. 5k-paced Mile Repeats

5K-paced mile repeats present a formidable challenge, regardless of your running pace. Consequently, it’s advisable to incorporate them into your training regimen during the 3-6 weeks leading up to a 5K or 10K race. This timing allows you to harness their benefits while ensuring you don’t exhaust your racing potential during your training sessions. 5K-paced mile repeats work your aerobic system at nearly your VO2max capacity, enhancing your running efficiency and optimizing the activation of fast-twitch muscle fibers.

Nonetheless, there are several important considerations when incorporating 5K-paced mile repeats. Firstly, it’s crucial to maintain control during these workouts. Exceeding your 5K race pace can transform long intervals into race-like efforts rather than training sessions. Secondly, it’s recommended to avoid durations that extend beyond 5-6 minutes, as working at or near your VO2max can lead to a rapid accumulation of lactate. If your pace falls outside this range, adjust either the duration or intensity of the intervals accordingly.

When preparing for a 5K race, you can employ 5K-paced mile repeats to develop race-specific fitness. In the initial stages of your training cycle, execute three one-mile repeats at your existing 5K pace, allowing 3-4 minutes of recovery between each repetition. As your race date draws nearer, increase the proximity of your pace to your target race pace during the repeats and reduce the recovery intervals to 90 seconds.

For longer-distance races, 5K-paced mile repeats can be integrated into your training regimen throughout the training cycle, especially in the earlier weeks, to enhance speed without compromising endurance.

Sample Workout:

1-2 mile warm-up
3 x 1 mile at your 5K race pace with 3-minute recovery intervals
1-2 mile cool-down

 

2. Threshold Pace Mile Repeats

Threshold pace represents the level of effort you could sustain for an entire hour if you were racing. This effort significantly enhances your aerobic fitness by challenging your body right at its lactate threshold, the point where anaerobic glycolysis kicks in and lactate accumulates rapidly in your bloodstream. Conducting mile repeats at threshold pace allows you to accumulate a greater training volume while minimizing the fatigue typically associated with training.

Threshold repeats can be integrated into your training program at any stage. In the early stages, they can serve as preparation for more extensive threshold workouts. These initial sessions, such as 4 to 6 x 1 mile at threshold pace, ready your body for longer workouts like 2-mile repeats or sustained tempo runs. During high-mileage marathon preparations, incorporating threshold pace mile repeats maximizes adaptation while mitigating the training-induced fatigue. Regardless of your skill level, threshold mile repeats involve shorter rest intervals, in contrast to the lengthier recovery periods employed in mile repeats conducted at 5K and 10K paces.

Alternatively, you can utilize slightly slower mile repeats at your half marathon pace to incorporate a higher training volume at your target pace with less fatigue compared to a continuous tempo run. For instance, about 2-4 weeks before your race, you might opt for 8 x 1 mile at your goal half marathon pace. This approach allows you to accumulate a substantial amount of training volume at your desired race pace without the risk of compromising your race-day performance. Marathoners will discover that executing extended intervals at threshold pace enables them to work at a higher volume close to their lactate threshold, even during the peak fatigue of marathon training.

Sample Workout:

1-2 mile warm-up
5-6 x 1 mile at threshold pace, with 1-minute recovery intervals
1-2 mile cool-down

 

3. Marathon Pace Mile Repeat Sessions

Performing mile repeats at marathon pace might initially feel relatively comfortable, and that’s precisely the reason for including them in your training regimen. During the first half of a marathon, your marathon pace should indeed feel reasonably comfortable. Training is the ideal time to master the art of maintaining the right intensity when running at marathon pace, and mile repeats at this pace serve as an effective tool for honing that control.

Marathon pace repeats are typically most beneficial when incorporated in the earlier stages of a training cycle, well before an athlete is ready for continuous marathon pace runs. For seasoned marathoners, integrating marathon pace workouts into long runs can be a valuable strategy.

Sample Workout:

1-2 mile warm-up
6-8 x 1 mile at marathon pace, with a 1-mile easy run in between
1-2 mile cool-down

Managing Pace During Mile Intervals

It’s crucial to emphasize that mile repeats should not be executed at race-level intensity. While it’s possible to achieve personal mile records during these workouts, especially for those who seldom participate in mile or 5K races, the primary emphasis should always be on pacing that aligns with the workout’s objective. The key indicator of running at an appropriate effort is whether you consistently have a reserve of energy left in your reserves, as opposed to finishing the workout utterly drained.

– Pacing holds significant importance. Strive for uniformity in your repetitions, often involving a degree of restraint in the initial repeat and a slight push in the concluding one. For more advice on pacing speed workouts, refer to the accompanying post.

– During recovery intervals, opt for a gentle jog or even a leisurely walk. If necessary, it’s entirely acceptable to mix walking and jogging. The primary purpose of these recovery segments is to reduce your heart rate and provide your body with sufficient respite to enable you to maintain a consistent effort in subsequent repetitions.

– In the absence of a track, any flat, uninterrupted section of road or trail will suffice.

– Always incorporate a warm-up routine that includes dynamic stretches and a minimum of 10 minutes of easy running.

 

4. V02 Max Interval Sessions

Similar to any speed-focused workout, it’s advisable to have a weekly running volume of at least 15-20 miles before incorporating speedwork. Ensure that your warm-up routine is adequate, encompassing dynamic stretches.

The quantity of intervals you should undertake hinges on your training volume and experience. Novice runners or those with lower weekly mileage may limit their VO2max intervals to a total of 10 minutes. Intermediate runners could extend their efforts to 12-16 minutes, while high-volume and elite runners might engage in up to 15-20 minutes of cumulative intervals.

For Novice Runners:

– Commence with a 10-minute warm-up at an easy, conversational pace.
– Perform 5 repetitions of 2 minutes of hard running, followed by 2 minutes of recovery jogging or walking.
– Conclude with a 5-10 minute cool-down at an easy pace.

For Intermediate/Experienced Runners:

– Initiate a 15-20 minute warm-up at an easy running pace.
– Execute 3-4 intervals of 4 minutes each at a pace resembling that of a 3K to 5K race effort, with 3 minutes of recovery jogging in between.
– Finish with a 15-20 minute cool-down at an easy running pace.

During the hard intervals, aim for an effort level of around 8-9 on a scale of 1-10, where 1 signifies a light jog and 10 represents an all-out sprint. The pace should mirror what you believe you could sustain if racing in a 3K to 5K event. During the recovery intervals, jog lightly as needed to restore your breathing to a normal rhythm.

 

5. Long Run with Surges

Introducing surges into your long runs is an effective way to begin incorporating long run workouts. Surges involve brief bursts of faster running integrated within a longer run. These bursts typically last for 1-2 minutes and are followed by ample recovery periods lasting 4-8 minutes. The intensity varies but usually falls within the range of a sustainable effort, such as lactate threshold to marathon pace.

Long runs with surges offer numerous advantages. They provide a safe introduction to faster running within long runs, whether it’s your first long run workout of the season or ever. These surges engage different energy systems without causing excessive fatigue. For competitive athletes preparing for races that require mid to late-race surges, long runs with surges simulate race day pacing.

Sample Workout:

90-minute surges long run: After a 20-minute warm-up, alternate 2-minute surges at half marathon effort with 6 minutes of easy running for the middle 60 minutes, then conclude with a 10-minute easy cool-down.

 

6. Progression Long Run

Progression long runs are designed to start at a controlled pace and finish faster. These workouts require the ability to maintain restraint initially and then dig deep as the run progresses. They are valuable for building both confidence and fitness, with a caveat – it’s essential to maintain good running form throughout. These runs are particularly beneficial for marathon and half marathon preparation, teaching smart race day pacing skills.

The intensity of progression long runs can be adjusted based on the training season. During base building and early training stages, the finish may involve a more moderate effort, while later in the training cycle, you might complete the final few miles at your goal race pace or slightly faster.

Sample Workout:

2-hour long run: Maintain an easy pace for most of the run, then ramp up to a moderate to moderately hard effort in the final 15 minutes.

 

7. Tempo Long Runs

Tempo long runs involve incorporating intervals of 20-30 minutes or 1-2 mile segments at a moderate to moderately hard effort within your long run. The tempo effort challenges your body’s ability to clear metabolic waste while sustaining a faster pace. Although not as fast as threshold running, the tempo pace typically falls in the range of half marathon to marathon effort.

These workouts are demanding and are best suited for experienced and injury-free runners. They allow you to combine two significant training stimuli in one session, increasing the intensity without compromising recovery between quality workouts. Tempo segments are best integrated into shorter long runs (approximately 90-120 minutes) due to the added demand.

Sample Workout:

20-minute warm-up
2 x 2 miles at half marathon pace with a 1/2 mile jog in between.
60 minutes of easy running

 

8. Marathon Pace Long Runs

For beginners, the primary goal is to complete the marathon. However, as you prepare for subsequent marathons, you can start incorporating marathon pace miles into your long runs.

Intermediate to advanced marathoners can benefit from including marathon pace workouts in their long runs. These workouts allow you to accumulate a substantial volume of marathon-specific work. It’s important to note that marathon pace is a physiological zone, so it’s crucial to base it on your current fitness level or slightly faster, rather than setting unrealistic goals.

Marathon-specific workouts help your body efficiently utilize energy at a moderate pace and teach you to maintain a sustained effort. Additionally, they provide an opportunity to practice fueling at a higher intensity, a vital skill for race day.

Sample Workout:

3-mile warm-up
6-8 x 1 mile at marathon pace with 1 mile of easy running in between
2-3 mile cool-down

 

Final Words – A Running Interval Guide

In conclusion, interval workouts are an invaluable tool in your running training arsenal. They offer a powerful means of rapidly improving your fitness levels and increasing your strength. These workouts, characterized by alternating high-intensity sprints and recovery periods of walking or jogging, can make a significant difference in your running performance.

While performing intervals on a track is ideal for precise speed measurement, it’s entirely possible to adapt them to road running by accurately measuring distances. Running intervals with fellow athletes can boost motivation and provide vital support during these challenging sessions.

Interval training delivers fast results by enhancing your running form, speed, endurance, and promoting fat burning. However, it’s essential to exercise moderation. Limiting interval workouts to once or twice a week is recommended to allow your body sufficient time to recover from the intense sessions.

In this post, we’ve explored what intervals are and how to incorporate them into your training regimen. You’ve learned about various types of interval workouts, including 5K-paced mile repeats, threshold pace mile repeats, marathon pace mile repeats, VO2 max intervals, and long runs with surges. Each of these workouts offers unique benefits and can be customized to suit your specific training goals.

We’ve also discussed the importance of factors like your experience level, training intensity distribution, periodization, individual recovery rate, and your unique strengths and weaknesses in planning interval sessions. By carefully considering these factors, you can tailor your interval training to maximize its effectiveness while minimizing the risk of overtraining or injury.

Incorporating intervals into your running routine can lead to remarkable improvements in your performance, whether you’re training for a 5K, half-marathon, marathon, or any other distance. Remember to focus on proper pacing, prioritize recovery, and gradually increase the intensity and volume of your interval workouts over time.

By following the guidelines and sample workouts provided in this post, you’ll be well on your way to harnessing the benefits of interval training and taking your running to new heights. So lace up those running shoes, hit the track or the road, and start reaping the rewards of interval workouts in your running journey.