Pop-art collage showing diverse people staying hydrated, including an office worker, busy adult, older person in recovery, and an athlete drinking water.

Different Bodies, Different Needs: Hydration for Everyday Life, Neurodivergence, Recovery and Sport

ByAbigail Longley

Why tailored hydration matters more than most people realise

First published at the Nutritional Harmony Blog (https://nutritionalharmony.blog), the companion site to our main platform at https://nutritionalharmony.co.uk.

Hydration advice is often presented as if everyone’s body works the same: “Just drink 8 glasses of water”, “Listen to your thirst”, or “Drink more on hot days.”
But in reality, hydration varies dramatically between people — because our lifestyles, bodies, sensory needs, and health conditions are different.

A desk-based adult, a neurodivergent person with interoception challenges, someone recovering from illness, and a marathon runner all have completely different hydration needs, barriers, and risks.

This article explores why hydration should be personalised — and offers practical strategies for each group.

Why Hydration Matters

Water is essential for:

  • Regulating body temperature
  • Supporting blood volume & circulation
  • Transporting nutrients and removing waste
  • Cognitive function, mood & concentration
  • Digestion and metabolism
  • Physical performance and endurance

Even 2% dehydration can impair concentration, energy levels, and exercise performance.
At 5% dehydration, aerobic capacity can drop by up to 30%.

Hydration isn’t just about how much you drink — it’s about how consistently and effectively your body maintains fluid balance.

1. The Office Worker: The “Daytime Dehydrator”

Why it happens

Modern desk work encourages long periods without movement or fluid. Many adults accidentally combine:

  • Hours of not drinking
  • High caffeine intake
  • Artificially cooled or heated office environments
  • “Catching up” by drinking most fluids in the evening

This creates a cycle of mild dehydration, afternoon fatigue, headaches, and poor sleep.

Signs someone may be under-hydrated during the workday

  • Mid-afternoon crashes
  • Brain fog
  • Headaches
  • Digestive sluggishness
  • Darker urine
  • Dry lips or skin

Better habits

  • Keep water visible (on the desk, in a favourite bottle)
  • Link drinking to routine actions (emails, toilet breaks, meetings)
  • Use urine colour as your guide
  • Aim to drink more in the morning and afternoon, less right before bed

2. Neurodivergent Individuals: Hydration Through a Sensory & Interoceptive Lens

Hydration challenges are very common among autistic and ADHD individuals — often due to interoception differences, sensory sensitivities, and executive function barriers.

Key challenges

Helpful, ND-friendly strategies

Hydration for neurodivergent people isn’t about “willpower” — it’s about supporting the brain in ways that truly work.

You can explore more posts on neurodiversity and nutrition here.

3. People Recovering from Illness or Surgery

Hydration needs change dramatically during recovery. Factors include fever, diarrhoea, stoma output, vomiting, blood loss, pain, low appetite, and medication effects.

Hydration plays a key role in digestion — especially for IBS or gut-related symptoms.

Why it’s challenging

  • Drinking can feel exhausting
  • Nausea reduces intake
  • Medications cause dry mouth or frequent urination
  • Fatigue reduces motivation
  • Appetite loss reduces water from food sources

Supportive hydration strategies

  • Sip little and often, instead of large glasses
  • Try gentle flavours (icing cold, mint, ginger, diluted juices)
  • Use oral rehydration solutions when appropriate:
  • Include hydrating foods (yoghurt, soups, fruit)
  • Monitor urine colour & frequency
  • Seek medical advice if unable to keep fluids down

Hydration directly supports healing, blood pressure stability, and digestive recovery.

If you struggle with low appetite during recovery, gentle hydration strategies pair well with low-energy cooking approaches.

4. Athletes & Exercisers: When Hydration Dictates Performance

For athletes, hydration affects:

  • Temperature regulation
  • Blood volume and oxygen delivery
  • Muscle function
  • Electrolyte balance
  • Endurance and strength

Why athletes must personalise hydration

Sweat losses vary enormously between individuals, and more so with:

  • Heat
  • Humidity
  • Exercise intensity
  • Clothing
  • Fitness level

Evidence-based guidelines

  • Daily intake: ~1 ml fluid per kcal burned
  • Before exercise: 5–7 ml/kg at least 4 hours prior
  • During exercise:
    • Calculate sweat rate
    • Replace gradually in 10–15 min intervals
  • After exercise: Replace 150% of the fluids lost

When to use sports drinks

  • >60 minutes of moderate–high intensity exercise
  • In hot/humid environments
  • Heavy sweaters
  • Events requiring both fluid + carbohydrate replacement

Helpful overview: https://www.bda.uk.com/resource/hydration-for-exercise.html

Common Hydration Mistakes (All Groups)

  • Only drinking when thirsty
  • Drinking most water late at night
  • Relying solely on caffeinated or sugary drinks
  • Forgetting to drink during hyperfocus
  • Not adjusting for heat or illness
  • Over-drinking plain water during endurance events
  • Ignoring dark urine or headaches

Better Hydration Habits for Everyone

  • Keep fluids visible and accessible
  • Sip regularly instead of gulping occasionally
  • Adjust intake based on heat, exercise, illness, and medication
  • Use urine colour as your guide
  • Choose drinks you genuinely enjoy (flavour matters!)
  • Include electrolytes for heavy sweating or long exercise
  • Build hydration into existing routines

Why Tailored Advice Works Better Than Generic Guidelines

Hydration is not “drink 8 glasses of water” — it’s a biological need influenced by:

  • Body size
  • Environment
  • Sensory processing
  • Physical health
  • Neurodivergence
  • Activity levels
  • Medications
  • Illness & recovery

When hydration advice is tailored, people feel better, perform better, and stay healthier.

Different bodies have different needs — and when we honour that, hydration becomes easier, more intuitive, and far more effective.

At Nutritional Harmony, I focus on personalised, accessible nutrition.
You can learn more about my approach on the About page.

If you’re new here, you can also read more about who I work with and my philosophy on my main website: https://nutritionalharmony.co.uk.