The CHALLENGE Trial · NEJM 2025

Exercise after colorectal cancer can save your life

A landmark Phase 3 trial just proved what many suspected: structured exercise after colorectal cancer treatment doesn't just help you feel better — it reduces recurrence and improves survival.

960
survivors
~7%
survival benefit
1 in 14
deaths prevented

The trial prescribed exercise in MET-hours per week — a measure of intensity × time. This calculator helps you track exactly that, using the same values from the trial.

The target dose

How much exercise is enough?

The CHALLENGE trial found benefit in the range of 20–27 MET-hours per week. To put that in everyday terms:

🚶
5 × 45-min brisk walks
= 15 MET-hours/week (good starting point)
🏃
3 × 30-min jogs + 2 × 30-min walks
= 24.5 MET-hours/week (CHALLENGE average)
🚲
4 × 45-min bike rides
= 21 MET-hours/week (above minimum)

You don't have to start here. The key is building gradually — increasing by about 2 MET-hours per week each month.

About you

How active are you right now?

This helps us suggest a realistic starting goal for you.

Your recovery

Where are you in your treatment journey?

Your personalised plan

Here's where to start

Suggested starting goal
MET-hours per week

Always discuss any new exercise plan with your oncologist or care team before starting.

Weekly Exercise MET-Hours Tracker
For colorectal cancer survivors · Based on the CHALLENGE trial protocol ·
⚠ Future dates cannot be logged
⚠ Sessions under 10 minutes don't count per the CHALLENGE protocol.

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Weekly Exercise · CHALLENGE Trial Tracker
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📋 Clinical Exercise Summary Report

Click "Generate report" to create your summary.
⚠ This summary is for informational purposes only and is not a substitute for clinical documentation. Review with your oncology or primary care team before including in medical records.
CHALLENGE protocol: Leisure-time aerobic activities ≥4 METs, ≥10 min only. Casual walking (<3 mph, ~3 METs) and resistance training are excluded.

The CHALLENGE protocol rules

🏃
Type
Aerobic only
Min. intensity
≥4 METs
Min. session
≥10 minutes

The CHALLENGE trial (NEJM, 2025) randomized 960 stage II–III colon cancer survivors to structured exercise. At 8 years, ~90% of exercisers were alive vs ~83% of controls — roughly 1 death prevented per 14 participants. Only leisure-time aerobic activity was counted. The default 24 MET-hrs/week matches the trial's average achieved dose.

NEJM publication →  ·  Plain-language guide →  ·  MET-hour explainer →

📈 How to build up to your goal

If you're just starting out, don't try to jump straight to 20–27 MET-hours in week one. The CHALLENGE program used a gradual ramp-up:

  • Start at a comfortable baseline and increase by ~2 MET-hours per week each month — for example, adding roughly 30 minutes of brisk walking per week.
  • Aim to reach 20 MET-hours/week as your first milestone — the minimum dose associated with survival benefit.
  • Once 20 is sustainable, continue building toward 27 MET-hours/week at a pace that feels manageable. There is no need to rush.
  • Always consult your oncology team before significantly increasing your exercise load.

🏋️ What about resistance training?

The CHALLENGE trial focused exclusively on aerobic exercise, so resistance training is not counted in this calculator. However, observational data suggest that resistance training may provide additional benefit when combined with aerobic exercise — not as a replacement. If you enjoy strength training, it is likely a worthwhile add-on to your aerobic routine. Read more about aerobic vs resistance training →

What is a MET-hour?

MET (Metabolic Equivalent of Task) measures energy use relative to rest. Brisk walking = 4 METs; jogging = 7 METs; running = 12 METs. Multiply the MET value by hours to get MET-hours. Example: 45 min of brisk walking = 4 × 0.75 = 3.0 MET-hours. Hitting 20–27 MET-hours/week matches the CHALLENGE dose. Casual walking (<3 mph, ~3 METs) falls below threshold and is not counted. Learn more →

Stay up to date on exercise and colorectal cancer research

Medical Disclaimer This tool is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. The information presented is based on published research and is not a substitute for guidance from your physician, oncologist, or qualified healthcare provider. Always consult your medical team before starting, modifying, or intensifying an exercise program — particularly following cancer treatment. Individual circumstances vary, and what is appropriate for one person may not be appropriate for another. Use of this calculator does not establish a patient–provider relationship.

MET-Hours Calculator for Colorectal Cancer Survivors

This free tool helps colorectal cancer (CRC) survivors track their weekly exercise dose using MET-hours — the exact metric used in the CHALLENGE trial, the landmark Phase 3 randomized controlled trial published in the New England Journal of Medicine in 2025. The trial demonstrated that structured aerobic exercise after stage II and III colon cancer treatment significantly improved disease-free and overall survival.

What is the CHALLENGE trial exercise dose?

The CHALLENGE trial (Colon Health and Life-Long Exercise Change) prescribed 20–27 MET-hours of aerobic exercise per week for colorectal cancer survivors. Participants who reached this target had approximately a 7% absolute improvement in overall survival at 8 years, with roughly 1 death prevented per 14 participants who adhered to the program. The trial enrolled 960 patients with high-risk stage II or stage III colon cancer who had completed adjuvant chemotherapy.

How do I calculate MET-hours after colorectal cancer?

MET (Metabolic Equivalent of Task) hours combine exercise intensity with duration. To calculate MET-hours, multiply the MET value of an activity by the number of hours performed. For example, brisk walking (4 METs) for 45 minutes equals 3.0 MET-hours. The CHALLENGE protocol counted only leisure-time aerobic activities at or above 4 METs, performed in bouts of at least 10 minutes. Common qualifying activities include brisk walking, jogging, running, cycling, lap swimming, and tennis.

Can I use this calculator for rectal cancer?

The CHALLENGE trial enrolled colon cancer patients specifically, but observational data — including findings from the EXERT trial and multiple cohort studies — suggest that similar exercise benefits likely extend to rectal cancer survivors. This calculator applies the same MET-hour framework and is used by both colon and rectal cancer survivors. Always discuss your exercise plan with your oncologist.

Exercise and colorectal cancer recurrence

Physical activity after colorectal cancer diagnosis has been associated with reduced recurrence risk and improved survival in multiple observational studies across cohorts including CALGB 89803, NCCTG N9741, and the Nurses' Health Study. The CHALLENGE trial provided the first Phase 3 randomized evidence confirming a causal relationship between structured exercise and improved outcomes. Survivors interested in learning more about the evidence can read the Colorectal Cancer Survivor Guide's plain-language summary of the CHALLENGE trial findings.

No data leaves your device — logs are saved in your browser only and never tracked.
Not medical advice. Always consult your oncology team before starting an exercise program.
Built for the Colorectal Cancer Survivor Guide