The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Heart Rate Zones and Weight Loss
Heart rate zones are intensity levels during exercise, measured as a percentage of your maximum heart rate. Understanding these zones helps you exercise effectively for weight loss. Whether you're building a weight management plan through exercise alone or alongside prescription weight loss medication, knowing your optimal heart rate range ensures you're training at the right intensity to achieve your goals safely and efficiently.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
What Are Heart Rate Zones?
Heart rate zones divide exercise intensity into five levels, each with specific benefits for fitness and weight loss. Your maximum heart rate is approximately 220 minus your age (in years). From this figure, zones are calculated as percentages:
- Zone 1 (50–60%): Very light activity, recovery
- Zone 2 (60–70%): Light aerobic work, fat burning
- Zone 3 (70–80%): Moderate aerobic, building fitness
- Zone 4 (80–90%): Hard anaerobic work, strength building
- Zone 5 (90–100%): Maximum effort, sprinting
For sustainable weight loss, most people benefit from exercising in zones 2–3, where your body efficiently burns fat whilst remaining able to sustain the effort. A fitness tracker or heart rate monitor helps you stay within your target zone during exercise.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Heart Rate Zones for Weight Loss and Exercise
Zone 2 (60–70% max heart rate) is often called the "fat-burning zone" because your body preferentially uses fat for energy at this lower intensity. However, total calorie burn matters for weight loss — higher intensity zones (3–4) burn more calories overall, even if a smaller percentage comes from fat. The best approach combines both: steady zone 2 sessions for base fitness and occasional zone 3–4 sessions for metabolic boost.
For weight management in the UK, the NHS recommends at least 150 minutes of moderate-intensity aerobic activity weekly. This typically falls into zones 2–3. Combine cardio with resistance training twice weekly to preserve muscle during weight loss and improve overall body composition.
Heart rate zone training works best alongside a calorie deficit achieved through diet. Use our free BMI calculator to assess your current weight status, and track your progress with our progress tracker as you combine exercise with dietary changes. If you're exploring prescription weight loss options, remember that medication like GLP-1 injections works best when paired with regular physical activity and healthy eating — exercise in your target heart rate zones supports these efforts and improves cardiovascular health throughout your weight loss journey.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
What is my maximum heart rate?
Your estimated maximum heart rate is 220 minus your age. For example, a 40-year-old has an approximate maximum heart rate of 180 beats per minute. This is an estimate — actual maximum varies by fitness level and genetics. If you have heart disease or take cardiac medication, consult your GP before using this formula.
Which heart rate zone is best for weight loss?
Zone 2 (60–70% max heart rate) is efficient for fat burning, but zone 3 (70–80%) burns more total calories. Combining both through steady-state zone 2 sessions and occasional zone 3 work optimises weight loss. The key is consistency — exercise you can sustain regularly is more effective than sporadic high-intensity work.
How do I calculate my heart rate zones?
First, estimate your max heart rate (220 minus your age). Then multiply this figure by each zone's percentage: Zone 2 is 60–70%, Zone 3 is 70–80%, and so on. For a 40-year-old with max HR of 180: Zone 2 = 108–126 bpm, Zone 3 = 126–144 bpm. A fitness watch or heart rate monitor tracks this automatically.
Can heart rate zone training help with weight management?
Yes. Zone 2–3 training improves aerobic fitness, increases calorie burn, and supports cardiovascular health — all important for sustainable weight loss. However, weight loss primarily depends on eating fewer calories than you burn. Exercise enhances results but works best alongside dietary changes and, if appropriate, weight management support from your GP.
Do I need a heart rate monitor for zone training?
A monitor is helpful but not essential. You can estimate intensity by how you feel — zone 2 allows conversation, zone 3 makes talking difficult. Many smartphones have built-in heart rate sensors, and affordable fitness trackers (£30–100) provide accurate zone data. For structured training, a monitor gives precise feedback and helps you stay consistent.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.