The exposure map method
Every sport shows a different set of body surfaces, at a different angle, for a different length of time, with a different thing removing protection from each. Map that and the plan writes itself.
An exposure map lists, for one sport, every body surface the sport presents to the sun, the angle at which it is presented, how long it stays presented, what removes protection from it, and which control actually holds there. It replaces a single global answer with a per-surface answer, which is the only kind that survives a long session, because different surfaces fail for entirely different reasons.
Most sun protection advice treats the body as one object with one answer. Apply this, reapply that, wear a hat. It is a reasonable starting point and it collapses the moment a session goes past an hour, because by then the surfaces of your body are in wildly different states. The tops of your thighs may be entirely intact. Your forehead is gone. Your ears were never done. Your neck is burning and you cannot see it.
The exposure map is a way of thinking that fixes this. It is not a product, a checklist you buy, or anything that requires equipment. It is five columns and one pass through your own sport, and it is the device this entire publication is built around.
The five columns
| Column | The question | Why it matters |
|---|---|---|
| Surface | Which part of the body is actually presented to the sky? | Sports do not expose bodies uniformly. A cyclist's forearms and a footballer's calves see completely different amounts |
| Angle | Is it facing the sun squarely, obliquely, or nearly edge on? | A surface facing straight up at midday receives far more than one facing sideways, which is why shoulders, the back of the neck and the tops of the thighs are the classic burn sites |
| Duration | How long does it stay in that position during the session? | A rotating forearm moves through many angles. A cyclist's neck holds one angle for hours. The static ones are worse |
| What removes protection | What is rubbing, wiping, soaking or covering it? | This is the column people never fill in, and it is the one that determines whether anything applied is still there |
| Control that holds | Given all of the above, what actually works here? | Sometimes cloth. Sometimes shade. Sometimes an application at a known break. Rarely the same answer twice |
How to build one for your sport
- Put the kit on and adopt the position you spend most of the session in. Not standing normally: on the bike, in a stance, bent over a bed of weeds, holding the tool.
- Look at what is facing upward. Those are your high-angle surfaces and they carry the largest load. Write them down first.
- Look at what is facing sideways and what is edge on. These matter less per hour but they still accumulate over a long day, and they include the ears, which almost nobody protects.
- Note everything touching skin. Every strap, band, collar, cuff, grip and pad. Those are your friction lines and they belong in column four.
- Note where sweat runs. Downhill from the scalp for almost everybody, and into the creases at the neck, elbow and knee.
- For each row, choose one control and be specific. Cloth, shade, timing, an application at a known break, or explicit acceptance. Acceptance is a legitimate answer. Vagueness is not.
- Check it against reality at the end of the season. Tan lines, strap outlines and the places that burned are the audit.
| Surface | Angle to the sun | Exposed for | What removes protection | Control that holds |
|---|---|---|---|---|
| Back of the neck | Almost straight up while bent over | 60-120 | Collar movement, sweat, and the fact that you cannot see it | A collar worn up or a brimmed hat. Product here is rarely reapplied |
| Upper back and shoulders | Facing the sky while kneeling or bent | 60-120 | A shirt riding up, strap movement | A shirt that stays put, chosen for length rather than for warmth |
| Backs of the hands | Directly upward, constantly | 60-120 | Soil, tools, gloves, washing | Gloves. Nothing applied survives handling soil |
| Forearms | Rotating through a wide arc | 60-120 | Sleeve edge, brambles, washing | Sleeves, which also solve the scratching problem |
| Ears and nose | High angle, always missed | 60-120 | Nothing much, they are simply never treated | A brimmed hat, which covers both in one move |
Why per-surface beats per-person
The instinct is to ask what someone should do. The exposure map replaces that with a set of smaller questions that each have a clear answer. It converts an unanswerable question, how do I protect myself for four hours, into five answerable ones, each of which has an obvious solution once the column four entry is filled in.
It also stops the most common failure mode, which is protecting the surfaces you can see and ignoring the ones you cannot. Every person reading this can picture their own face. Almost nobody can picture the back of their own neck, the tops of their ears, the parting in their hair or the back of their calves, and those are precisely the surfaces that get missed.
The exposure map is the reason we do not treat sweat as a weaker version of swimming. Immersion acts on every submerged surface at once, which is why a single global answer is reasonable for a swimmer.
In land sport the surfaces diverge. Some are under cloth, some under a strap, some in constant sweat drainage, some barely touched. A single global answer cannot be correct for all of them, and any advice that offers one has stopped describing your sport.
The angle column, in slightly more detail
Angle is the column people find least intuitive, so it is worth a note. Solar radiation arriving at a surface depends on how squarely that surface faces the source. A horizontal surface at the middle of the day is the extreme case, which is why shoulders, the tops of forearms, the bridge of the nose, the tops of the ears, a parting in the hair and the tops of the thighs when seated are the reliable burn sites across every sport.
It also explains a few things that surprise people. Cyclists burn the back of the neck because riding position turns it from a near-vertical surface into a near-horizontal one. Gardeners burn the same place for the same reason. Golfers burn the left forearm and the left side of the neck more than the right if they are right handed, because of address position and the direction of play on most rounds. Runners burn shoulders and the tops of the ears.
Reflection adds to this. A surface facing downward or sideways can still receive a substantial load where the ground is reflective. Snow is the strongest common reflector, which is why under-chin and under-nose burning is a known feature of days on snow. Pale rock, concrete, sand and water all reflect more than grass or dark tarmac.
Filling in column four properly
This is where most maps go wrong, because it is the column that requires being specific about your own kit rather than about sport in general. The prompts that help:
- What touches this surface, and does it move? Anything that moves is removing protection.
- Does sweat drain across it or collect on it?
- Do you wipe it, deliberately or otherwise? Faces, brows and forearms get wiped constantly.
- Does it get washed, gritted or chalked? Hands in soil, chalk on a climb, grit on a trail.
- Is it covered for part of the session and uncovered for the rest? Rolled sleeves and removed hats create partial exposure that nobody plans for.
The controls that appear in column five
| Control | Best for | Weakness |
|---|---|---|
| Move the session | Any surface, any sport, any duration | Fixtures, shifts and winter daylight remove the option |
| Cloth | High-friction and high-angle surfaces, long sessions | Heat, rules of the sport, and comfort |
| Shade on the route | Everything, at no cost | Not available on open moor, pitch, course or site |
| Applied product | Surfaces with low friction that cloth will not cover | Degrades unevenly, invisibly and on a schedule you cannot verify |
| Explicit acceptance | Surfaces where nothing holds, such as palms on a climb | Only legitimate when the exposure is genuinely small |
An exposure map is a planning tool for exposure, not a health assessment. It does not tell you anything about your skin, your risk or any mark on your body. For anything of that kind, see a GP or the NHS. The British Association of Dermatologists and Cancer Research UK both publish plain guidance on what to look out for.
Using it across a season
The map is most useful when it is treated like any other part of a training log: written once, reviewed at the end of a block, and updated when something changes. A new helmet moves a strap line. A change from a road bike to a gravel bike changes riding position and therefore neck angle. A move from summer league to winter league changes the hours entirely. A new job changes everything.
The rest of this site is a set of worked maps. Running, cycling, hill days, racquet sports, field sports, golf, climbing, gardening and outdoor work each get their own, because the columns come out differently every time. Read the one for your sport, then build your own, because your kit is not the same as anybody else's.
Questions
Do I need to write an exposure map down?
Once, yes. The value is in being forced through column four, which is the one people skip when they do it in their head. After that it becomes automatic and only needs revisiting when your kit, your sport or your season changes.
How is this different from just wearing sun cream and a hat?
It tells you where the hat and the cream will and will not work, which is the part that decides whether the plan survives four hours. A hat does nothing for the back of a cyclist's neck. Cream does nothing under a moving strap. The map makes both of those visible before the session rather than after it.
Which surfaces come out worst most often?
Across almost every sport: the back of the neck, the tops of the ears, the nose, a parting in the hair, the backs of the hands and the tops of the shoulders. They share two properties, a high angle to the sun and being invisible to the person they belong to.
Does the map work for children's sport?
The method is the same, but the responsibility sits with whoever is running the session rather than with the child, which changes column five. A club's answer has to be about shade, kit policy and session timing, because it cannot depend on twenty individuals reapplying anything.
Is an exposure map any use in winter?
Yes, particularly on snow and at altitude, where the reflected component turns surfaces that face downwards into exposed ones. It is also useful for spring, when the sun climbs quickly, people are back outdoors in volume, and almost nobody has adjusted their plan yet.
This article has no commercial links. Nothing in it is sponsored, no product is named and no payment of any kind was received for anything written here. Water Resistant SPF is published by Northbank Media and recommends no products at all. Our funding is set out in full on the about page.
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