If your priority is indoor training
The Training Cloud is the altitude tent for indoor cycling, running, rowing, and S&C work.
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Your space. Your training.
Indoor altitude training
Create a controlled altitude environment for your indoor bike, treadmill or rower.
The Training Cloud is sized to fit a full smart trainer setup, a treadmill, a rower, or a strength bench. Pair it with Zwift, Wahoo, TrainerRoad, or your normal indoor session, and your sea-level workout becomes a 2,500m (8,202ft) workout. Used by Cameron Wurf of INEOS Grenadiers and IRONMAN, who trains across both disciplines from his Box Altitude tent.
Why Layer Altitude Onto Your Indoor Training Time
You are already spending hours per week on a smart trainer, a treadmill, or a rower. The infrastructure is in place. The session is on the calendar.
Adding altitude requires no additional time commitment, no schedule restructuring, and no separate altitude block. The same workout, in the same time slot, with a higher physiological signal.
This is the efficiency case for indoor altitude training. For age-group triathletes managing 15-plus hours per week around work and family, for serious cyclists racing on Zwift or training for events at altitude, and for runners doing structured treadmill work, the indoor altitude protocol is the lowest-friction way to access altitude training.
It also stacks. Train inside the tent during the day. Sleep at altitude at night. Two physiological signals running in the same 24-hour cycle, in the same space.
What Fits Inside the Training Cloud
The Training Cloud is a four-poster tent measuring 2.6m long, 1.3m wide, and 2.3m high. The footprint accommodates the full range of indoor training equipment used by serious athletes.
2.6m
Length
1.3m
Width
2.3m
Height
- Smart trainer with road or TT bike. Wahoo Kickr, Tacx Neo, Zwift Hub, Saris H3, Elite Suito, and full smart bike platforms (Wahoo Kickr Bike, Stages SB20, Wattbike Atom). Includes the bike, the trainer, the head unit, and a small fan inside the footprint.
- Standard home treadmill. Most domestic treadmills (NordicTrack, Sole, Woodway H, ProForm) fit within the 2.6m × 1.3m floor area.
- Concept2 rower or RowErg. Standard Concept2 footprint fits the tent length.
- Strength bench and bodyweight setup. Adjustable bench, kettlebells, dumbbells, and bodyweight S&C work all fit. Squat racks and barbells generally do not.
- Combined setups. Many athletes rotate equipment through the same tent across the week — bike for cycling sessions, treadmill for running, bench for strength.
Altitude Training for Zwift, Wahoo, and TrainerRoad
Altitude training for Zwift is straightforward. Set up your smart trainer inside the Training Cloud, connect to Zwift on a tablet or laptop, and run your normal session at simulated altitude.
ANT+ and Bluetooth signals pass through the tent walls without significant attenuation. Wahoo Kickr, Tacx Neo, Zwift Hub, and other smart trainers pair normally with Zwift, TrainerRoad, Rouvy, FulGaz, and Wahoo SYSTM.
Garmin head units, Wahoo Bolt and Roam, and ANT+ heart rate monitors all work as expected. A small fan inside the tent maintains airflow during high-intensity sessions.
The session itself runs the same way. The difference is the metabolic cost. Your heart rate is higher for the same wattage. Ventilation is higher.
Power, Heart Rate, and RPE at Altitude
Absolute power drops at altitude. For most riders, the reduction is 5 to 15% for the same RPE compared to sea level. A rider with a 300W FTP at sea level typically holds 255 to 285W at 2,500m for the same effort.
This means power-based training inside the tent does not work the same way. Most coaches train indoor altitude sessions to heart rate or RPE rather than power. Three practical approaches.
- Heart rate-based zones. Run your normal HR-based zone targets. Power will be lower than sea-level equivalents but the metabolic stimulus is appropriate.
- Adjusted FTP at altitude. Set a separate altitude FTP based on a 20-minute test inside the tent. Run TrainerRoad or Zwift workouts at altitude FTP rather than sea-level FTP. Most riders find their altitude FTP sits 8 to 12% below their sea-level FTP at 2,500m.
- RPE-based intervals. Train threshold and VO₂ max work to perceived effort. Sustainable hard effort is sustainable hard effort regardless of the wattage on the screen. This is how most professional riders run altitude indoor sessions.
The choice depends on your training style. The protocol works equally well with all three as long as you stop expecting sea-level wattages on the screen.
Pain Cave Altitude Setup: Practical Considerations
Building a pain cave altitude setup requires four practical decisions.
- Floor space. The Training Cloud needs 2.6m × 1.3m of floor space, plus access room around the entry. Most pain caves comfortably accommodate this.
- Ceiling height. The tent is 2.3m tall. Standard ceiling heights of 2.4m or higher work without modification. Lower ceilings or basement spaces with exposed pipework may need spatial planning.
- Generator placement. The F10 or F20 altitude generator sits beside the tent and connects via a hose. Generator placement should allow airflow around the unit and access for maintenance. The generators run at 57 to 62 dB and generate some heat, so a well-ventilated space is preferred.
- Ventilation and temperature. Indoor training generates heat. Altitude training generates more heat per session because the cardiovascular system is working harder. A small fan inside the tent and good airflow in the wider space keep core temperature manageable. The Training Cloud's spacious geometry helps with this.
Treadmill Running and Rowing Inside the Tent
- Treadmill running. Standard home treadmills fit within the 2.6m × 1.3m floor area. Run intervals, tempos, threshold work, or steady aerobic sessions at altitude. Pace will be 8 to 15% slower than sea level for the same RPE.
- Rowing. Concept2 rowers and most other indoor rowers fit the tent length. Run altitude pieces, intervals, or steady-state rowing sessions.
- Cross-training. A single Training Cloud covers cycling, running, and rowing for multi-discipline athletes. Triathletes who train all three indoors can run their entire indoor schedule from the same tent.
For sport-specific protocols, see altitude training for cycling, altitude training for triathlon, or altitude training for running.
Stack With Overnight Altitude Exposure
Indoor altitude training is one half of the full protocol. Overnight altitude exposure is the other half.
For athletes who want a dedicated training tent in the pain cave and a separate altitude environment in the bedroom, the Training Cloud + Sleep Cloud combination is common. Train in the Training Cloud during the day. Sleep in the Sleep Cloud overnight. Two systems running on the same protocol, in two spaces.
For athletes who want their entire bedroom converted to altitude rather than a tent in the room, the Altitude Bedroom System covers a whole room. Indoor training continues to happen in the Training Cloud or in a separately configured altitude space.
Match Your Indoor Training Setup to the Right Box Altitude System
Three configurations cover three indoor training profiles.
If you want indoor training plus dedicated overnight sleep
Pair a Training Cloud in your pain cave with a Sleep Cloud in your bedroom. Two systems, two spaces, full-protocol coverage. Suits athletes whose pain cave is not in the bedroom and who want both functions on dedicated infrastructure.
Shop Training Cloud and Sleep CloudOr convert your whole bedroom into an altitude environment with the Altitude Bedroom System and run a separate Training Cloud for the pain cave.
Request a Bedroom System QuoteIf your priority is overnight adaptation, with occasional indoor altitude work
The Sleep Cloud is the cleanest overnight protocol. Run your indoor training at sea level. Sleep at altitude. The sleep tent is for sleep, not active training. Suits athletes who do most of their training outdoors and want a clean LHTL implementation.
Shop Sleep CloudTrusted by Athletes Who Train Indoors at the Highest Level
Cameron Wurf, INEOS Grenadiers professional cyclist and elite IRONMAN triathlete, runs altitude blocks in his Box Altitude tent across both disciplines. The protocol fits inside his existing indoor training schedule rather than replacing any part of it. The Queensland Academy of Sport supplies its athletes with Box Altitude systems.
Cameron WurfINEOS Grenadiers & IRONMAN
Queensland Academy of SportSupplies athletes with Box Altitude
For deeper performance focus, see altitude training for performance or read the how-to guide of sleeping at altitude.
Frequently Asked Questions About Indoor Altitude Training Setups
Yes. The Training Cloud is sized to accommodate a full smart trainer setup including a road or TT bike. Wahoo Kickr, Tacx Neo, Zwift Hub, Saris H3, and full smart bike platforms (Wahoo Kickr Bike, Stages SB20, Wattbike Atom) all fit within the 2.6m × 1.3m floor area along with the bike and a small fan.
Yes. ANT+ and Bluetooth signals pass through the tent walls without significant attenuation. Smart trainers pair normally with Zwift, TrainerRoad, Rouvy, FulGaz, Wahoo SYSTM, and other indoor cycling platforms. Most riders place the tablet or laptop on a stand inside or just outside the tent.
Absolute power drops 5 to 15% at altitude for the same RPE. Most riders set a separate altitude FTP based on a 20-minute test inside the tent — typically 8 to 12% below sea-level FTP at 2,500m. Run altitude indoor sessions to that adjusted FTP, or train to heart rate or RPE rather than power. Stop expecting sea-level wattages on the screen.
A small fan inside the tent is recommended for high-intensity indoor cycling sessions. The Training Cloud's spacious geometry helps with temperature management, but indoor altitude training generates more heat than equivalent sea-level work because cardiovascular load is higher. Standard pain cave fan setups (Wahoo Headwind or equivalent) work normally inside the tent.
Most standard home treadmills fit within the 2.6m × 1.3m floor area, including NordicTrack, Sole, ProForm, and most Woodway models. Commercial-grade treadmills with extended frames may not fit. Check the footprint of your specific treadmill against the tent dimensions before purchase.
For more, see the full FAQ.
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Build your indoor altitude training setup with the Box Altitude system that fits your space and your training plan.
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