When we think about workouts designed to improve your VO₂ max, it’s important to understand how the training elicits the specific physiological adaptations that influence VO₂ max. VO₂ max improvement happens when your heart muscle becomes stronger and is able to deliver larger amounts of oxygenated blood to your muscles. More specifically, your cardiac function is improved through training in a few different ways. First, your training – endurance-effort training as well as interval workouts such as those provided below – increases your core body temperature which results in an increase in blood plasma volume and therefore an increase in your total blood volume. Second, the heart muscle responds just like any other muscle does to increased demands in training and gets stronger, which improves the strength of each heartbeat. As a result of your training, then, you have more blood volume available and your heart can pump greater volume with each heartbeat. These two improvements combine to provide more oxygenated blood to your muscles with every heartbeat.

It’s important to remember, though, that each individual athlete has a natural limit to their VO₂ max, and VO₂ max improvement based on their genetics, fitness, and age. Once you have achieved your individual limit for VO₂ max you can still achieve improvements in performance by increasing your pace/power at your aerobic ceiling as well as your aerobic endurance. These two factors, in fact, are often considered better predictors of performance than VO₂ max.

Your aerobic ceiling is the heart rate at which you switch from relying primarily on your aerobic energy system – your oxygen-driven energy system – to relying on our anaerobic energy system; this is also commonly referred to as your anaerobic threshold or your lactate threshold. As your VO₂ max stabilizes, so does your lactate threshold heart rate (which, by the way, will often become lower as your VO₂ max improves). However, training can still elicit improvements in your pace/power at your lactate threshold; in other words, even when your VO2 Max stabilizes, you can still get faster.

Your aerobic endurance drives how long you can sustain any given effort level at or below your aerobic ceiling (efforts above that ceiling are limited to a matter of minutes, regardless of your fitness). Training that improves your endurance at your aerobic ceiling will cascade down to improve your endurance at every aerobic-driven effort level, which happens to include appropriate effort levels for all triathlon distances.

So, sure, go ahead and pay attention to improving your VO₂ max through training, because you certainly don’t want to ignore an area of potential. But that shouldn’t be the only goal of your training. By incorporating training that can both improve your VO₂ max and also improve your speed and endurance at lactate threshold, you are covering the widest range of areas for potential gains on race day.

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Notes for all the VO₂ max workouts

Each workout has A, B, and C variations, which correspond to varying “degrees of difficulty,” with A being the hardest. Look over each option and choose the variation that is appropriate for your current level of fitness and your recent training. (Keep in mind that you can be an “advanced” triathlete who hasn’t been in the pool in several months or a “beginner” triathlete who recently qualified for the Boston Marathon; experience and current fitness aren’t the same thing.)

Training zones are provided within each workout. The following table summarizes those training zones and specifies rates of perceived exertion and pace, power, and/or heart rate targets for each. For disciplines where you don’t have recently updated data for your lactate threshold heart rate (LTHR) for bike and run (they are different!), threshold paces for swim and run, and/or your FTP for the bike, use rate of perceived exertion (RPE).

	Swim	Bike	Run
Warm-Up / Cool-Down / Easy / Recovery (RPE 3/10)	15” slower per 100 than threshold pace	50-60% FTP / 65-80% of LTHR*	About 3’ slower per mile than 5k**/threshold pace / 65-85% of LTHR*
Endurance (RPE 4/10)	10” slower per 100 than threshold pace	60-75% of FTP / 81-89% of LTHR	About 2’ slower per mile than 5k/threshold pace / 85-89% of LTHR
Tempo (RPE 5/10)	5” slower per 100 than threshold pace	75-85% of FTP / 89-93% of LTHR	45” slower per mile than 5k/threshold pace / 89-94% of LTHR
Sub-Threshold (RPE 6/10)	2” slower per 100 than threshold pace	85-95% FTP / 93-96% of LTHR	10k effort / 15” slower per mile than 5k/threshold pace / 94-97% of LTHR
Threshold (RPE 7/10)	Threshold pace	95-105% FTP / 96-99% of LTHR	5k/threshold effort / 97-99% of LTHR
VO2 Max (RPE 8/10)	2” faster per 100 than threshold pace	105-120% FTP / 99-102% of LTHR	3k effort / 15” per mile faster than 5k/threshold pace / 99-102% of LTHR
Anaerobic (RPE 9/10)	5” faster per 100 than threshold pace	120-135% FTP / 102-106% of LTHR	1-mile effort / 30” faster per mile than 5k/threshold pace / 102-106% of LTHR

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* If you are executing the workouts using heart rate metrics, please keep in mind that heart rate is a lagging indicator. It can take several minutes for heart rate to align with your effort level (even longer during your warm-up) so the heart rate targets provided often won’t be hit during the shorter intervals.

** You can use your current 5k pace as a proxy for your threshold run pace if needed; the two are not exactly the same but they will be close enough.

Workouts to increase your aerobic ceiling

These swim, bike, and run workouts focus on interval efforts that are just above your lactate threshold. In fact, we refer to this effort level as “VO₂ max Effort.” By working at this effort level for a few minutes at a time, with sufficient recovery so that you can sustain your VO2 Max Effort for the duration of the interval set, you can both increase your power/pace at your aerobic ceiling and provide room for an increase in VO₂ max.

VO₂ max Swim Workout

2850 (A), 2450 (B), or 2000 (C) meters/yards

400 Warm-up (A/B) / 200 Warm-up (C) (feel free to mix in some backstroke and breaststroke during your warm-up)

6x 50 Drill (on plenty of rest, nice and easy so you can focus on form)

Primer Set, 6x through (A/B) / 4x through (C):

25 at Anaerobic Effort (5″ Rest Interval)

25 at Anaerobic Effort (5″ RI)

25 Easy (10” RI)

100 Easy (alternate backstroke and freestyle)

Main Set #1, 4x through:

150 (A) / 100 (B/C) at VO2 Max Effort (10” RI)

50 Easy (10” RI)

100 Easy (alternate backstroke and freestyle)

Main Set #2, 4x through:

100 (A) / 75 (B) / 50 (C) at VO2 Max Effort (10” RI)

50 Easy (A) / 25 Easy (B/C) (10” RI)

100 Cool-down (again, feel free to mix in some backstroke and breaststroke during your warm up)

VO₂ max Bike Workout

60 Minutes

10’ Warm-up

Primer Set:

30” at Sub-Threshold Effort / 30” Easy

30” at Threshold Effort / 30” Easy

30” at VO2 Max Effort / 30” Easy

30” at Anaerobic Effort / 30” Easy

30” at Anaerobic Effort / 30” Easy

5’ Easy (RPE 3 / 50% FTP / 75-80% of LTHR)

Main Set (A):

3’ at VO2 Max Effort / 3’ Easy

Main Set (B), 2 sets:

4x through … 2’ at VO2 Max Effort / 2’ Easy

+ Extra 2’ Easy between sets

Main Set (C), 3 sets:

4x through … 1’ at VO2 Max Effort / 1’ Easy

+ Extra 3’ Easy between sets

Cool-down to finish

VO₂ max Run Workout

60 minutes (A/B) / 45 minutes (C)

10’ Warm-up

Primer Set, 5x through:

30” build to Anaerobic Effort

30” Easy

5’ Easy

Main Set, 6x through (A/C) / 8x through (B):

3’ (A) / 2’ (B) / 1’ (C) at VO₂ max Effort

3’ (A) / 2’ (B) / 90” (C) Easy

Cool-down to finish

Workouts to improve aerobic endurance

These swim, bike, and run workouts improve your high-end aerobic endurance and are the crux of learning to go faster for longer. By combining Threshold and Sub-Threshold effort levels, these workouts allow you to perform at or near your lactate threshold for relatively long intervals. Longer intervals at/near lactate threshold place create demands on your heart, which can improve VO₂ max, and also acclimate you both physiologically and psychologically to sustaining hard efforts.

VO₂ max Swim Workout

2900 (A), 2550 (B), or 2150 (C) meters/yards

300 Warm-up (A/B) / 200 Warm-up (C) (feel free to mix in some backstroke and breaststroke during your warm up)

Primer Set, 2x through with paddles but no buoy:

75 (A) / 50 (B/C) at Tempo Effort (10″ Rest Interval)

75 (A) / 50 (B/C) just below Threshold Effort (10“ RI)

75 (A) / 50 (B/C) at Threshold Effort (10” RI)

75 (A) / 50 (B/C) just above Threshold Effort (10” RI)

100 Easy (alternate backstroke and freestyle)

Main Set, 3x through:

200 (A/B) / 150 (C) at Threshold Effort (10” RI)

100 just below Threshold Effort (5″ RI)

200 (A) / 150 (B) / 100 (C) at Threshold Effort (5” RI)

100 Tempo (A) / Easy (B/C) (10″ RI)

100 Cool-down (again, feel free to mix in some backstroke and breaststroke during your warm up)

VO₂ max Bike Workout

60 Minutes

10’ Warm Up

Ramp:

2’ at Endurance Effort

1’ at Tempo Effort

1’ at Sub-Threshold Effort

1’ at Threshold Effort

2’ Easy

Primer Set, 5x through:

30” at VO2 Max Effort

30” Easy

3’ Easy

Main Set, 3x through:

3’ (A/B) / 2’ (C) at Threshold Effort (A/B) / Sub-Threshold Effort (C)

30” Rest (B/C only)

3’ (A/C) / 2’ (B) at Sub-Threshold Effort (A/B) / Threshold Effort (C)

30” Rest (B/C only)

3’ (A) / 2’ (B/C) at Threshold Effort (A/B) / Sub-Threshold Effort (C)

2’ (A) / 3’ (B/C) Easy

Cool-down to finish

VO₂ max Run Workout

75 Minutes (A) / 60 Minutes (B) / 45 Minutes (C)

15’ Warm Up (A/B) / 10’ Warm Up (C)

Primer Set, 5x through (A/B) / 3x through (C):

30” build to Anaerobic Effort / 1-Mile Pace

30” Easy

5’ Easy (A/B) / 2’ Easy (C)

Main Set, 4x through (A) / 3x through (B/C):

2’ at Threshold Effort (A/B) / Sub-Threshold Effort (C)

30” Easy (B/C only)

4’ (A) / 3’ (B) / 1’ (C) at Sub-Threshold Effort (A/B) / Threshold Effort (C)

30” Easy (B/C only)

2’ at Threshold Effort (A/B) / Sub-Threshold Effort (C)

4’ (A/C) / 3’ (B) Easy

Cool-down to finish