VO2 Max:  This workout will increase your VO2 max and reduce your chances dying.

Warm up/ Tissue prep:
3 mins of gentle cardio pulse raiser, use the same modality you are going to use in the workout.

Core:
McGill Sit up 5-30 seconds x 4 hand/ leg combinations
Side plank max duration e/s, scale to use your knee if needed
Bird dogs x 10

Have a stretch

Jump back on the cardio and spend a few minutes building up to zone 4.

Main Effort: VO2 max builder protocol 1
30 seconds as hard as you can go, 30 seconds gentle recovery
5 repetitions, rest 2 minutes, 5 more repetitions
NB: As hard as you can go for 30s, it should hurt!

Scaling:
S: 5 x 30/30
M: 5 x 30/30, 2 mins rest, 5 x 30/30
L: 5 x 30/30, 2 mins rest, 5 x 30/30, 2 mins rest, 5 x 30/30
XL: 5 x 30/30, 2 mins rest, 5 x 30/30, 2 mins rest, 5 x 30/30, 2 mins rest 5 x 30/30

Top tips:
Find a friend to suffer with and hold you accountable
NB you probably won't get your HR as high as you would on a 4 minute max effort, but you should be working much harder for the 30s.
This is best done in a safe environment on cardio equipment rather than anywhere you need to maintain situational awareness

Photo by Fabian Møller on Unsplash