February Longevity Challenge
February Longevity Challenge - Improve VO2max with HIIT
For our February challenge, we are focusing on optimizing your cardiorespiratory fitness. More specifically, we’re challenging you (and ourselves) to increase your VO2max through high-intensity interval training (HIIT).
“The two metrics that are most significantly associated with longevity are incredible cardiorespiratory fitness as measured by VO2max, and strength” - Dr Peter Attia
The challenge
The aims of this month's challenge are to:
- Gain experience of training at a high intensity that will improve your VO2max
- Explore how you can incorporate HIIT training into your regular exercise protocol
- Measure your VO2max to determine your present cardiorespiratory health and set a benchmark for future progress
The challenge will take place across the last full week of this month (Feb 20 - 26), and include three levels:
- Beginner: Complete 1 HIIT session during the week + Measure your VO2max on the weekend
- Intermediate: Complete 2 HIIT sessions interspersed with 1 moderate-intensity continuous training (MICT) session during the week + Measure your VO2max on the weekend
- Advanced: Complete a modified Hickson protocol (3 HIIT sessions interspersed with 2 MICT sessions) during the week + Measure your VO2max on the weekend
What is VO2max and why does it matter?
VO2max is a measure of the maximum amount of oxygen your body can use during exercise. In other words, it’s the volume of oxygen that is taken in and used to power your muscles when you are working at the highest intensity you can manage.
Improving your VO2max
Without training, VO2max tends to decline with age (by about 7% in women and 10% in men per decade after the age of 25) [12]. But the good news is that you can improve your VO2max at any age, as shown by the recent case of the 101-year-old cyclist who increased his by 13% after 2 years of focused training! [13]
The most effective way to improve VO2max is high-intensity interval training (HIIT), which involves bursts of high-intensity exercise between low-intensity recovery periods. The table below shows some examples of HIIT protocols that we recommend for this month’s challenge.
For the advanced level of this month’s challenge, we’re suggesting that you complete any HIIT protocol three times on alternate days and complete two moderate-intensity continuous training (MICT) sessions on the days in between.
This regimen is based on several well researched protocols for improving VO2 max, including the Rønnestad [14] and Hickson protocols [15]. The Hickson protocol is an intense week-long regimen that resulted in some of the largest published increase in VO2max, despite the fact it was developed in 1977. It involves training 6 days/week, with alternate days of HIIT and MICT. Note that the MICT is not a slow zone 2 cardio jog - it essentially requires you to run as fast as you can manage for 40 minutes!
At the bottom of this blog post (below the comments section) you can find more detailed advice about selecting a HIIT protocol that suits you, along with more example protocols.
Measuring VO2max
It’s important to know your VO2max so that you have an idea of your current cardiorespiratory fitness and can judge how effective your efforts to improve it are. That’s why we want you to finish your challenge week by measuring your VO2max.
VO2max is most accurately measured in a lab by monitoring how much oxygen your body uses as you exercise up to almost the point of exhaustion. This type of test typically costs between $100-250 and takes about an hour. Alternatively, some smartwatches and wearables provide you with an estimation of VO2max based on your age and your heart rate during exercise, but for our challenge we recommend performing the 3-minute step test since it is quick, simple, and accessible to almost everyone.
The 3-minute step test
For this challenge (if a lab test is inaccessible) we recommend that you measure your VO2max with the 3-minute step test, which studies have validated as accurate [16]. Instructions for performing the test are shown in the graphic below.
If you aren’t able to weigh yourself or measure your height, you can use this online calculator to calculate your VO2max with just your age and your heart rate after the step test.
Join the community!
This challenge, like any other, is much easier with the support of other people, so join our Longevity Challenges for 2023 community where we will be:
- Providing further useful information about the challenge as well as details about future challenges
- Posting about our own preparation and experiences undertaking the challenge
- Answering any questions relating to the medical, scientific and/or practical aspects of this and other longevity challenges - we’re a team of doctors, longevity scientists, and enthusiasts who are keen to share our knowledge!
Zest Guide: Choosing your HIIT protocol
Factors you should consider when choosing your HIIT protocol are:
- Duration of high-intensity intervals and recovery periods, and the number of total intervals: There is debate as to whether longer (3-8 min) or shorter (30-90 sec) HIIT intervals are better for improving VO2max. However, both have shown to be highly effective.
- Exercise modality: Cycling, running (treadmill or hill sprints), assault bike, rowing and bodyweight/lighter-weight strength exercises (burpees, push presses etc.) are all great options with different advantages.
This is not a challenge where one size fits all and it’s critical you factor in your wider athletic goals, strengths/weaknesses, preferences, and injuries when picking your HIIT protocol.
Below are some specific HIIT protocols you may want to consider. Members of the Zest team will also share their specific protocols ahead of the challenge for further ideas:
- Beginners - exercise bike; 4 × 4-min intervals at 85-95% max heart rate (HR), separated by 4-min recovery periods at 65% HR. (This is a protocol Peter Attia has referenced doing himself.)
- Intermediate/Advanced - experiment with an assault bike, rower, or other more whole body movements. Try both longer (Hickson protocol) or shorter intervals (Rønnestad protocol) in different sessions with the goal of identifying what you enjoy most so that you can get closest to hitting 30 minutes in the white-hot VO2max zone per workout.
Hickson protocol [15]
- 6 days of training, with alternate days of HIIT and MICT.
- HIIT sessions are 6 × 5-min high-intensity intervals on an exercise bike, interspersed with 2-min active rest periods.
- MICT is a 40-minute run at the fastest pace you are able to maintain for that duration.
Rønnestad protocol [14]
- 2 HIIT sessions per week, supplemented with lower-intensity/endurance-paced workouts on days in between.
- For each HIIT session, (after a solid warmup) perform 30 seconds at all-out intensity, then 15 seconds of recovery, and repeat for 10 minutes, followed by a 3-min rest period. Repeat this series of intervals 3 times.
- Increase your power output on high-intensity intervals as your fitness builds, always eliciting a near maximal effort.
