The hidden side of UTA Recovery: Gut, hormones, kidneys & the post-race blues after UTA

Most runners think recovery is about one thing:

Sore legs and when can I return to training.

But after Ultra Trail Australia, the real story is much bigger.

Because what you feel (tight quads, stiff calves) is only the surface.

Underneath, your body is dealing with:

• Gut disruption

• Hormonal imbalance

• Kidney stress

• Immune suppression

• Nervous system fatigue

• And often… a mental and energy crash

Understanding this is what separates runners who:

✅ Recover properly and improve

❌ Feel flat, sick or injured for weeks

1. Your gut takes a bigger hit than you think

If you struggled to eat after your race, you’re not alone.

During long endurance events, blood flow is redirected away from the gut to working muscles.

Over hours, this can lead to:

• Nausea

• Bloating

• Diarrhoea

• Reduced appetite

• Intestinal irritation

Research in ultra runners has shown actual epithelial injury to the gut lining after long races.

Why this matters

If your gut isn’t functioning well:

• You won’t refuel properly

• Recovery slows

• Energy levels crash

• Immune function drops

What to do

First 24–48 hours after a long run:

• Eat simple, easy-to-digest foods

• Small, frequent meals

• Avoid heavy/ fatty meals early

Good options:

• Rice, toast, fruit

• Smoothies

• Yoghurt

• Soups

Avoid

• Large heavy meals immediately

• Excess alcohol

• Aggressive “clean eating resets”

Your gut needs recovery, not restriction

2. Hormones: Why you feel flat after an ultra

After long ultras (especially 100km+), your body shifts into a catabolic state.

Research in 100 mile runners shows:

• ↑ Cortisol (stress hormone)

• ↓ Testosterone

• Reduced anabolic (recovery) signals

What this feels like:

• Low energy

• Poor motivation

• Flat mood

• Reduced drive to train

Why it matters

This hormonal environment means:

Your body is not ready for hard training, start small and increase as your body allows.

Trying to push through this phase:

• Delays recovery

• Increases injury risk

• Worsens fatigue

What to do

• Prioritise sleep

• Eat enough (especially carbs), aiming for consistent meals across the day.

• Reduce life stress where possible

• Delay intensity, include low intensity exercise such as walking, recovery swim etc.

Think: rebuild first, train later.

3. Kidneys & Hydration: The silent stress

Long endurance events can place temporary stress on the kidneys.

This is influenced by:

• Dehydration

• Muscle breakdown

• Heat

• NSAID use

In many cases, kidney function returns to normal within 24–48 hours.

But here’s the catch:

When things go wrong, it’s usually because runners:

• Don’t rehydrate properly

• Ignore symptoms

• Continue pushing too early

What to monitor

Good signs:

• Urine; aim for light colour.

• Regular urination

• Stable energy levels.

Red flags:

• Very dark urine

• Minimal urination

• Swelling

• Nausea

• Unusual fatigue

IF THESE OCCUR, it is recommended to present to the emergency department ASAP

If in doubt: get it checked

4. The immune system dip

After ultras, your immune system is temporarily suppressed.

This is why many runners get sick in the week after racing.

Contributing factors:

• High physiological stress

• Poor sleep

• Energy deficit

• Travel exposure (hello UTA crowds)

What to do

• Prioritise sleep

• Eat enough

• Avoid high-intensity training early

• Wash hands / basic hygiene

• Don’t jump straight back into busy environments if exhausted

This is not the time to “push through”

5. The post-race blues (ps..no one talks about this)

You’ve trained for months.

You’ve had the high of race day.

Then suddenly…

it’s over

Many runners experience:

• Low mood

• Lack of motivation

• Emotional flatness

• Loss of direction

This is commonly called:

Post-race blues

Why it happens

• Loss of structure

• Hormonal changes

• Nervous system fatigue

• Emotional comedown

Studies in endurance athletes show:

• Fatigue increases

• Vigour decreases

• Mood can take 1-4 weeks to normalise

What to do

• Expect it (this is normal)

• Plan something small post-race

• Stay connected socially

• Avoid making big decisions immediately

• Reintroduce routine gradually

You don’t need a new race goal straight away

6. Sleep: The overlooked recovery multiplier

Sleep is often disrupted after ultras due to:

• Nervous system activation

• Muscle soreness

• Hormonal changes

Even if night 1 is poor:

Night 2 and 3 are critical

Practical tips:

• Prioritise early nights

• Short naps are okay

• Keep caffeine low

• Create a calm evening routine

Bringing It All Together

After UTA, your body isn’t just recovering from exercise.

It’s recovering from:

• Metabolic stress

• Hormonal shifts

• Gut disruption

• Nervous system fatigue

• Emotional load

The Runners Who Recover Best Do This:

They don’t just think:

“My legs feel okay”

They think:

“Is my whole system recovered?”

The Takeaway

If you ignore these hidden systems:

• Recovery drags out

• Fatigue lingers

• Injuries creep in

If you respect them:

• You recover faster

• You train better

• You perform better next time

Up Next

In Blog 5 we’ll cover:

The biggest mistakes runners make after ultras (and how they lead to injury, illness and poor performance)

Including:

• Why runners get Achilles pain after races

• The danger of returning too fast

• How to rebuild safely

This is Dietitian Imogen Haines & Coach Adam Clarke, signing off for now!

You can book an appointment with Darren, Natalia or Newcastle Knights Physiotherapists Katie or Hayd'n at www.upnadamptphysio.com for any injuries or if you want to become better at what you do.

Bookings also available on our website for the following services at Up N Adam Performance Training & Physiotherapy:

• Aerobic Ceiling & VO2 Max testing - to discover more effective ways to train efficiently www.flowitri.com.au

• Strength & Conditioning Programs or Coaching - contact us or book via the website or email us at upnadamptphysio@gmail.com

• Remedial Massage - to relieve accumulative muscle tension & keep you training well.

• CycleFit by Physiotherapist Dean Waterman - At Up N Adam, for all your bike fitting solutions www.cyclefitphysio.com

• Dietitian - Sweat testing, weight-loss or to optimise your training nutrition / fuelling www.nutrientnation.com.au