Mythbuster
High-Intensity Interval Training (HIIT) makes basic aerobic endurance training (LISS) superfluous. Mythbuster: High-Intensity Interval Training (HIIT) makes basic aerobic endurance training (LISS) superfluous. High-Intensity Interval Training (HIIT) makes basic aerobic endurance training (LISS) superfluous.
Summary
HIIT and LISS are not competitors but complement each other: HIIT efficiently increases VO₂max, while Zone-2 training (LISS) improves mitochondria, capillarization, and recovery capacity without burdening strength training. The evidence supports a combined approach, not replacing LISS with HIIT.
Mythbuster: High-Intensity Interval Training (HIIT) makes basic aerobic endurance training (LISS) superfluous.
The Myth
High-Intensity Interval Training (HIIT) makes basic aerobic endurance training (LISS) superfluous.
What the Evidence Says
HIIT efficiently builds maximal oxygen uptake (VO_2max), but it places heavy demands on the nervous system and requires longer recovery. Zone-2 cardio (LISS) is irreplaceable for increasing mitochondrial density, capillarization, and lactate-free recovery capacity without negatively impacting strength training.
Practice: Concrete Implementation
The evidence does not say "HIIT instead of LISS," but rather "HIIT and LISS, properly dosed." The art lies in combining both stimuli so that you build VO₂max and mitochondria without ruining your strength training or your recovery.
Example A — Weekly Plan (Strength + Endurance Combined)
Suppose you train strength 4× per week and want to add endurance. Here's what a balanced week looks like:
| Day | Session | Intensity | Duration | Purpose |
|---|---|---|---|---|
| Mon | Strength (lower body) | heavy | 60–75 min | Maximal strength |
| Tue | LISS Zone 2 (bike/walk) | easy, nasal breathing | 40–60 min | Mitochondria, capillaries |
| Wed | Rest or mobility | – | – | Recovery |
| Thu | Strength (upper body) | heavy | 60 min | Maximal strength |
| Fri | HIIT (bike/ergometer) | 4–6 × 30 s all-out, 3–4 min rest | 20–25 min | VO₂max |
| Sat | LISS Zone 2 | easy | 45–60 min | Aerobic base |
| Sun | Rest | – | – | Recovery |
Note: Never do HIIT directly before a heavy strength session. At least 24 h apart, better 48 h.
Example B — Execution & Coaching Cues
LISS (Zone 2):
- Intensity: you can still hold a conversation, breathe preferably through your nose.
- Heart rate roughly 60–70% of HRmax (rule of thumb: 180 minus age).
- Cue: "Easy, steady, no ego." If you can no longer speak, you're going too fast.
HIIT:
- Intervals: 4–6 × 30 s "all-out" with 3–4 min easy recovery (classic Wingate format).
- Cue: "The first repetition feels too easy — that's correct."
- After the last interval, cool down for 5–10 min.
Order: If you do strength and endurance on the same day, do strength first, then cardio — or with ≥ 6 h between them.
Example C — Microcycle (4 Weeks)
| Week | LISS Sessions | HIIT Sessions | Note |
|---|---|---|---|
| 1 | 2 × 45 min | 1 × 4 intervals | Introduction, technique |
| 2 | 2 × 50 min | 1 × 5 intervals | +1 interval |
| 3 | 3 × 45 min | 1 × 6 intervals | Volume up |
| 4 | 2 × 40 min | 1 × 4 intervals | Deload |
After 4 weeks: 1 easy week (LISS only), then repeat the cycle.
Ideal: 3–4 LISS sessions + 1–2 HIIT sessions per week, cleanly planned around strength training.
Good enough: 2 LISS + 1 HIIT per week if time is tight — that covers both stimuli.
First step: Add a single additional Zone-2 session (30–40 min) per week and keep HIIT at 1× per week for now.
Continue at the source
Read the original sourceFAQ
Can I completely replace HIIT with LISS?
No. LISS primarily improves the aerobic base (mitochondria, capillarization, fat metabolism), but does not achieve the high VO₂max stimuli of HIIT. Conversely, HIIT cannot build the aerobic base as efficiently as LISS. Both stimuli cover different adaptations.
How many HIIT sessions per week make sense if I also train strength?
As a rule, 1–2 HIIT sessions per week. More places too much stress on the nervous system and recovery and can impair strength gains and recovery. It's important to keep at least 24–48 h between HIIT and heavy strength sessions.
How do I know if I'm training in Zone 2 (LISS)?
You can still hold a normal conversation, breathe preferably through your nose, and feel relaxed. A rough guide is a heart rate of about 60–70% of maximal heart rate (rule of thumb: 180 minus age). If you can no longer speak, you're going too intensely.