Exercise & Warm Weather - June 2026: Managing Warm Weather With Health Conditions — How to Stay Active Safely
- Jun 26
- 10 min read
Author: Jamie Pickett, Clinical Exercise Physiologist, Health Facilitator, & Founder of My Movement Medicine.
Length: 10 minute read
Category: Exercise, Heart Health, Cardiac Rehabilitation, Seasonal Health
Warm weather can make exercise feel harder, especially with heart conditions, diabetes, respiratory problems or other long-term conditions. This guide explains how to stay active safely, adjust intensity, manage hydration and recognise warning signs.
Introduction
Warm weather can feel great.
It can lift mood, encourage people to get outside, and make walking feel more appealing. But for people living with heart conditions, high blood pressure, diabetes, respiratory conditions, kidney problems, neurological conditions, or reduced mobility, warm weather can also make exercise feel harder and increase the risk of dehydration, dizziness, heat exhaustion, and symptom flare-ups.
This does not mean you need to stop exercising in summer.
It means you need a smarter plan.
The goal is not to “push through” the heat. The goal is to keep moving safely, adjust your effort, and know when to change the session.
For people attending Phase 4 cardiac rehabilitation in London, exercising online, or building up activity independently, warm weather planning is part of safe, sensible exercise.
“An ounce of prevention is worth a pound of cure.” — Benjamin Franklin
Why warm weather affects the body
When the temperature rises, your body has to work harder to keep cool.
It does this by:
sending more blood towards the skin
increasing sweating
increasing breathing rate slightly
increasing heart rate for the same activity
using more fluid and salts
This means an exercise session that normally feels comfortable may feel harder in hot weather.
A walk that usually feels like Borg RPE 10–11 might suddenly feel like RPE 13–14.
You have not necessarily lost fitness. Your body is simply dealing with an extra stressor: heat.
What this means for you
In warm weather, the session goal changes.
Instead of aiming to progress, aim to maintain.
A good warm-weather plan should help you:
keep active without overheating
reduce the risk of dehydration
avoid exercising at the hottest part of the day
lower intensity when needed
recognise warning signs early
protect your confidence and routine
When it is too hot to exercise
There are times when the safest exercise plan is not to exercise.
As a simple rule, if the temperature is around 35°C or above, structured exercise is not recommended, especially if you live with a heart condition, diabetes, respiratory condition, heart failure, kidney disease, reduced mobility, or you take medication that affects blood pressure, heart rate, fluid balance or sweating.
This includes outdoor exercise, hard indoor exercise, circuits, intervals, heavy strength work, long walks, hill walking, and anything that makes you hotter.
At this level of heat, the aim is not to “keep the streak going”. The aim is to stay cool and safe.
On very hot days:
do not complete outdoor exercise
avoid structured exercise sessions unless you are in a genuinely cool, well-ventilated indoor environment
do not try to hit your usual step count or exercise target
avoid hills, intervals, circuits, heavy strength work, or anything that makes you hotter
keep movement to essential daily activity and very gentle mobility only
focus on cooling, hydration where appropriate, shade, rest, and checking in on vulnerable people
A missed workout in extreme heat is not a failure. It is sensible risk management.
You can restart your routine when the temperature drops and your body feels normal again.
Who needs to be more careful?
Anyone can become unwell in hot weather, but extra care is needed if you:
have a heart condition
have heart failure
have high or low blood pressure
take diuretics or blood pressure medication
have diabetes
have kidney disease
have a respiratory condition such as COPD or asthma
are older
live alone
have reduced mobility
have had a recent hospital admission
are recovering from illness
are exercising after a long break
You may also need to be more cautious if you are taking medications that affect fluid balance, blood pressure, heart rate, sweating, or kidney function.
Do not stop prescribed medication because it is hot. If you are unsure how your medication interacts with hot weather, ask your GP, pharmacist, cardiac nurse, heart failure nurse, or relevant specialist.
Heart conditions and warm weather
Hot weather can place extra demand on the cardiovascular system.
The heart may need to pump more blood towards the skin to help with cooling. At the same time, sweating can reduce fluid levels, which may lower blood pressure and increase dizziness, especially when standing up quickly.
This is why some people notice:
higher heart rate than usual
lower blood pressure
dizziness when standing
more fatigue
heavier legs
reduced exercise tolerance
palpitations
feeling “washed out” after activity
If you use heart rate targets, be aware that heart rate can be less predictable in hot weather. Use the talk test and Borg RPE 6–20 as your main guide.
A sensible warm-weather target for many people is:
RPE 9–11 for easier activity
RPE 11–13 for light to moderate activity
avoid pushing hard if you feel overheated, dizzy, unusually breathless, or unwell
You should be able to talk comfortably. If you cannot speak in full sentences, reduce the effort or stop.
Heart failure and fluid restriction
This needs a special mention.
Many warm-weather articles simply say “drink more water”. That is not always straightforward if you have heart failure and have been advised to restrict fluids.
If you are on a fluid restriction, follow your clinical team’s advice.
You can still reduce heat stress by:
staying in cooler rooms
using fans or cool cloths
avoiding exercise during the hottest part of the day
wearing loose, light clothing
keeping activity gentle
asking your heart failure nurse or GP what to do during heatwaves
Do not guess your fluid allowance. Get individual advice.
“Listen to your body. It is smarter than your schedule.”
Diabetes and warm weather
Warm weather can affect diabetes management.
The main issues include:
dehydration
changes in blood glucose levels
reduced appetite
more sweating
increased risk of hypos for some people if exercising
problems storing insulin or glucose monitoring equipment safely
If you have diabetes, it may help to:
check blood glucose as advised
carry hypo treatment if relevant
avoid long walks in the hottest part of the day
keep medication and equipment out of direct heat
plan meals and fluids before activity
reduce exercise intensity on very hot days
A short, easy walk after a meal may still be useful, but keep it sensible. On hot days, 10 minutes indoors or in shade may be better than 30 minutes outside in direct sun.
Respiratory conditions and heat
Warm weather can make breathing feel more difficult for some people, especially if heat is combined with humidity, poor air quality, or high pollen levels.
If you have asthma, COPD, or another respiratory condition:
keep your inhaler or medication with you if prescribed
avoid busy roads if air quality feels poor
choose shaded or greener routes
reduce intensity
use indoor options on very hot or humid days
stop if breathlessness feels unusual or does not settle
The best session is the one you can complete safely and recover from well.
The warm-weather exercise rule: reduce before you remove
You do not always need to cancel exercise.
Often, the better approach is:
Reduce before you remove.
That means you can reduce:
duration
intensity
speed
hills
resistance
number of rounds
time outdoors
complexity of exercises
For example:
30-minute walk becomes 10–15 minutes
outdoor walk becomes indoor marching
circuit session becomes seated strength
intervals become steady movement
strength session becomes one set instead of three
evening class becomes online at home if travel feels too much
Keeping the habit alive matters.
Best times to exercise in warm weather
Try to exercise:
earlier in the morning
later in the evening
indoors where possible
in shade
in well-ventilated spaces
Avoid exercising in the strongest sun, especially around late morning to mid-afternoon.
If the weather is very hot, humid, or there are heat-health alerts, keep the session lighter than usual.
Hydration: simple but individual
For most people, drinking regularly in warm weather is important.
Water is a good first choice. Other drinks can also contribute, but be mindful of alcohol, which can worsen dehydration and affect judgement.
Practical hydration tips:
drink earlier in the day, not only after symptoms start
take water to sessions or walks
sip regularly
check urine colour as a rough guide, unless this is affected by medication or supplements
eat water-rich foods such as fruit, yoghurt, soups, salads, and vegetables
replace fluids after sweating
But remember: if you have been told to restrict fluids, follow your personalised medical advice.
Clothing and environment
Small changes can make a big difference.
Try:
light, loose clothing
breathable layers
comfortable shoes
a hat outdoors
sunglasses if needed
sunscreen
shaded routes
sitting breaks
cooler rooms
closing curtains or blinds during the hottest part of the day
opening windows when the outside temperature drops
If you are exercising online, set up the room before the session:
water nearby
fan if suitable
chair available
phone nearby
medication nearby if relevant
clear space
reduce screen brightness if glare is an issue
Warning signs: when to stop
Stop exercising and cool down if you notice:
dizziness
feeling faint
confusion
nausea
headache
heavy sweating with weakness
muscle cramps
unusual breathlessness
chest pain or pressure
palpitations with feeling unwell
clammy skin
extreme fatigue
feeling hot but not sweating
Move to a cooler place. Sit or lie down. Sip fluids if appropriate. Use cool cloths or a fan. Ask for help if symptoms do not settle.
Heat exhaustion and heatstroke
Heat exhaustion can usually improve if you cool down quickly.
Possible symptoms include:
tiredness
weakness
dizziness
headache
muscle cramps
feeling sick
heavy sweating
thirst
Heatstroke is more serious and needs emergency help.
Signs may include:
confusion
loss of consciousness
very high temperature
hot skin
seizures
symptoms not improving after cooling
If someone is unwell and not improving, treat it seriously and seek urgent medical help.
“The first wealth is health.” — Ralph Waldo Emerson
A warm-weather exercise plan
Use this simple structure when the weather is hot.
Option 1: Cooler day
5–10 minute warm-up
20–30 minutes walking or light circuit
RPE 11–13
5–10 minute cool-down
hydration before and after
Option 2: Hot day
5–10 minute warm-up
10–20 minutes easier activity
RPE 9–11
more rest breaks
indoor or shaded route
longer cool-down
Option 3: Very hot day, heat alert, or temperatures around 35°C or above
This is not a day to train.
Focus on:
staying indoors or in shade
keeping cool
drinking fluids if appropriate for you
following any fluid restriction advice if you have heart failure
avoiding unnecessary travel
checking in on vulnerable friends, family or neighbours
doing only gentle movement needed for comfort, such as easy walking around the home, working on mobility and stretching, or relaxed breathwork
If your home is also very hot, even indoor exercise may not be appropriate.
The goal is simple:
stay cool, stay safe, and return to exercise when conditions are safer.
Warm-weather home circuit
Try this on hot days when outdoor walking is not sensible.
Complete 1–2 rounds.
Keep the effort light.
1. Seated marching
1 minute
2. Sit-to-stand or supported chair rise
8–10 repetitions
3. Wall press-up
8–10 repetitions
4. Seated knee extensions
8–10 each side
5. Standing heel raises holding a chair
8–12 repetitions
6. Shoulder rolls and relaxed breathing
1 minute
Keep the whole circuit around RPE 7–10.
You should feel better afterwards, not wiped out.
Warm-weather walking checklist
Before walking, ask:
Is it already too hot?
Is there shade?
Do I have water?
Do I have my phone?
Do I need medication with me?
Can I shorten the route?
Do I have a cool place to return to?
Do I feel well enough today?
During the walk, ask:
Can I talk comfortably?
Am I getting dizzy?
Is my breathing normal for me?
Am I sweating excessively or feeling weak?
Do I need to stop early?
After the walk, ask:
Did I recover well?
Do I feel better or worse?
Was the route sensible?
Should I choose an easier option next time?
Common mistakes in warm weather
Mistake 1: Using the same pace as usual
Heat makes the same pace harder. Slow down before symptoms build.
Mistake 2: Exercising at midday
Choose morning, evening, indoors, or shade where possible.
Mistake 3: Waiting until thirsty
Thirst can lag behind need. Drink regularly unless you have been advised to restrict fluids.
Mistake 4: Ignoring medication considerations
Some medication affects blood pressure, fluid balance, or heart rate. Ask your pharmacist or clinician if unsure.
Mistake 5: Cancelling everything
Often, the best option is a smaller session, not no session.
SMART challenges
Short-term SMART challenge: 7-day heat-smart movement plan
Specific: Complete 3 heat-smart movement sessions this week.
Measurable: Record 3 sessions.
Achievable: Each session can be 10–20 minutes and completed indoors or outside during cooler hours.
Relevant: Keeps your movement routine going without pushing hard in the heat.
Time-bound: Complete within 7 days.
Long-term SMART challenge: summer safety habit
Specific: For 4 weeks, check the weather, choose the safest exercise time, and record your RPE after each session.
Measurable: Complete this for 12 exercise sessions.
Achievable: Use a simple note on your phone or calendar.
Relevant: Helps you understand how heat affects your body and exercise tolerance.
Time-bound: Continue for 4 weeks, then review patterns.
How My Movement Medicine can help
My Movement Medicine can help you stay active safely through warm weather with structured, adaptable exercise.
Our face-to-face C.I.C. sessions in Hampstead provide supervised, heart-conscious exercise with longer warm-ups, cool-downs, pacing support, and a friendly group environment.
Our online C.I.C. sessions are a useful option when travel, heat, symptoms, or energy levels make it harder to attend in person.
Both options use the talk test, Borg RPE 6–20, and adaptable exercise choices so you can keep moving without feeling pressured to overdo it.
The best first step is to try a session and build from there.
Frequently asked questions
Should I exercise during a heatwave?
It depends on the heat level, your condition, symptoms, medication, and environment. On very hot days, choose indoor, gentle movement or rest if needed.
Is it safe to walk in hot weather with a heart condition?
It may be safe for some people if the walk is short, shaded, low intensity, and completed during cooler hours. If symptoms are unstable, seek medical advice first.
Why is my heart rate higher in the heat?
Your body sends more blood to the skin to help cool you. This can increase heart rate for the same activity.
What if I am on fluid restriction?
Follow your personalised advice. Speak to your GP, heart failure nurse, or specialist team about managing hot weather safely.
Can I do online exercise instead?
Yes. Online exercise can be a useful way to keep routine when travel or heat makes face-to-face attendance harder.
Recommended books
The Heat Will Kill You First — Jeff Goodell
A readable explanation of how heat affects human health and why hot weather planning matters.
Exercised — Daniel Lieberman
A useful book for understanding movement, effort, and how exercise fits into real life.
The Comfort Crisis — Michael Easter
A broader book on resilience and health behaviours, useful when thinking about adapting to challenging environments without being reckless.
Summary
Warm weather does not always mean you have to stop exercising.
It means you need to adapt.
Reduce intensity, choose cooler times, stay hydrated where appropriate, avoid the strongest sun, and pay attention to symptoms. If you live with a heart condition, diabetes, respiratory condition, heart failure, or another long-term condition, your warm-weather plan should be individual and sensible.
But extreme heat is different.
As a simple rule, if a red heat alert is declared / if temperatures are around 35°C or above, structured exercise is not recommended. On those days, prioritise cooling, hydration where appropriate, shade, rest, and safety. Gentle movement around the home is enough if it feels comfortable and your environment is cool enough.
The aim is simple:
Keep the habit when it is safe. Lower the heat stress. Stay safe.
This health guide was written by Jamie Pickett, Clinical Exercise Physiologist, Health Facilitator, & Founder of My Movement Medicine.
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