Summary:
These ten VO2 running sessions give you different ways to include very hard efforts within your half marathon training. With the amount of Zone 5 work and recovery changing between workouts, you can explore different ways to structure this demanding intensity within your preparation.
Stepping Up the Intensity in Half Marathon Training
Half marathon training often involves spending plenty of time at intensities you can sustain for longer, which gives Zone 5 a very different role within your preparation. These sessions take you into very hard running for shorter periods, with recovery giving you the chance to repeat that intensity rather than trying to sustain it continuously.
The ten workouts below give you different ways to structure that work. Some divide Zone 5 into shorter repetitions, while others ask you to stay with the effort for longer before recovering. The amount of very hard running can also vary between sessions, so there is no need to treat the workout with the most Zone 5 work as the one you should eventually reach. Choose a session that makes sense alongside the rest of your half marathon training and adjust the amount of work when you need to.
Explore your zones with our Where Do Running Zones Fit Into Half Marathon Training? guide, which explains the intensity metrics used across the different zones and how they can contribute to your preparation.
10 Example VO2 Workouts for Half Marathon
1. 2-Minute Repeats
Purpose: Accumulates repeated periods of very hard running while the recoveries help you maintain the intended intensity across the full session.
Warm-Up: 10 min jog
Main Set: 5 x 2 min @ Zone 5 (2 min recovery between)
Cool-Down: 10 min jog
2. Short Interval Set
Purpose: Uses short repetitions to maintain pace and running quality across repeated high-intensity efforts.
Warm-Up: 10 min jog
Main Set: 8 x 1 min @ Zone 5 (1 min recovery between)
Cool-Down: 10 min jog
3. VO2 Pyramid
Purpose: Develops pacing control across changing interval lengths, requiring you to adjust your pace while keeping each effort within Zone 5.
Warm-Up: 10 min jog
Main Set: 1 min → 2 min → 3 min → 2 min → 1 min @ Zone 5 (2 min recovery between)
Cool-Down: 10 min jog
4. Threshold Into VO2 Intervals
Purpose: Adds shorter Zone 5 efforts after sustained threshold work, challenging you to increase the intensity when fatigue is already present.
Warm-Up: 10 min jog
Main Set:
8 min @ Zone 4
3 x 90 sec @ Zone 5 (90 sec recovery between)Cool-Down: 10 min jog
5. 400m Repeats
Purpose: Develops your ability to maintain your running mechanics at higher speeds across repeated efforts.
Warm-Up: 12 min jog
Main Set: 6 x 400m @ Zone 5 effort (90 sec recovery between)
Cool-Down: 8 min jog
6. Broken VO2 Sets
Purpose: Uses a longer recovery between sets to restore enough capacity to maintain the pace and quality of the second block.
Warm-Up: 10 min jog
Main Set: 2 x (4 x 1 min @ Zone 5) (1 min recovery between, 3 min between sets)
Cool-Down: 10 min jog
7. Uphill VO2 Repeats
Purpose: Uses the incline to increase the force required with each stride, adding a greater muscular demand to the Zone 5 work.
Warm-Up: 10 min jog
Main Set: 5 x 60 sec uphill @ Zone 5 (walk down recovery between)
Cool-Down: 10 min jog
8. VO2 With Strides
Purpose: Finishes the session with brief faster running, giving you practice maintaining speed and coordination after the longer Zone 5 efforts.
Warm-Up: 10 min jog
Main Set:
4 x 2 min @ Zone 5 (2 min recovery between)
4 x 20 sec strides (40 sec recovery between)
Cool-Down: 10 min jog
9. Long VO2 Intervals
Purpose: Increases the time you must sustain each Zone 5 effort before recovery, placing greater emphasis on maintaining intensity through the later stages of each interval.
Warm-Up: 15 min jog
Main Set: 3 x 3 min @ Zone 5 (2:30 recovery between)
Cool-Down: 10 min jog
10. Tempo Into VO2 Intervals
Purpose: Introduces Zone 5 work after sustained tempo running, requiring you to increase the intensity after fatigue has already started to develop.
Warm-Up: 12 min jog
Main Set:
10 min @ Zone 3
3 x 90 sec @ Zone 5 (2 min recovery between)Cool-Down: 10 min jog
Finding a Place for Zone 5 in Your Half Marathon Training
Very hard running does not need to take up a large part of your half marathon training to have a place within it. Zone 5 gives you a way to introduce a distinctly higher intensity alongside the more sustained running that forms much of your preparation. How much of that work you include can change depending on your training and how well you are recovering.
Because these sessions can carry a substantial recovery demand, where you place them matters. Consider what you have already done and what you have coming next rather than looking at the workout on its own. There may be weeks when Zone 5 fits comfortably and others when the wider demands of your half marathon training mean very hard running is better kept shorter or left for another time.
Learn more about Zone 5 in our How VO2 Training Develops Half Marathon Performance guide, which explores how this type of training can influence your aerobic capacity and contribute to performance across the distance.
Final Thoughts
Zone 5 can bring a very different challenge to half marathon training, giving you the chance to step away from longer sustained efforts and experience the demands of very hard running. These sessions can be tough, but they can also add some welcome variety when you are ready for a change of pace.
The ten workouts give you a collection to draw from rather than something you need to work through. You may enjoy returning to certain sessions or find that different workouts suit you as your half marathon training develops. Very hard running deserves appropriate recovery, so give yourself time before asking your body to take on another demanding session.
Always consult with a medical professional or certified coach before beginning any new training program. The information provided is for educational purposes only and is not a substitute for personalized advice.
