Zone 5: VO₂max — Your Aerobic Ceiling

Zone 5: VO₂max — Your Aerobic Ceiling

Zone 5 is short, intense, and demanding. These efforts push your cardiovascular system to its limits — increasing the maximum amount of oxygen you can absorb and use.

Why Zone 5 Helps Triathletes

Boosts your VO₂max

A higher VO₂max gives you more aerobic room to work with — everything below becomes easier.

Improves your ability to handle surges

Hills, accelerations, overtaking — Zone 5 preps you for them.

Strengthens fast-twitch fibres aerobically

Even your explosive fibres adapt to endurance under Zone 5 stress.

Faster recovery between high-intensity efforts

Your system learns to clear waste products more efficiently.

What Zone 5 Feels Like

• Hard breathing

• Burning legs

• Short intervals only

• Full focus and effort

You can’t hold this long — and that’s the point.

Simple Zone 5 Session

6 × 2 minutes hard with 3 minutes very easy

You should feel close to your limit each rep.

Zone 5 gives you that extra gear.