You already know which “gears” (zones) to train in and how to drive “off-road” (on the trail). Now let's talk about how to plan your “route” (training plan) and how to watch the “gauges” so you notice in time that the “fuel” is running low or the “engine” is overheating.

6.1. Hours, Not Kilometers

We've already agreed that in trail running, pace is a relative concept. So the first rule of planning: measure your load in hours, not kilometers.

Ten hours of training per week is a clear and comparable quantity wherever you run. But 100 km per week? 100 km through a flat park and 100 km in the mountains with 5000 meters of elevation gain are two utterly different loads.

An even more precise metric is calories. Modern watches estimate energy expenditure fairly accurately. If you know that your hard workout costs 1500 kcal and your easy one costs 700 kcal, you can plan your load very flexibly without being tied to kilometers, or even to hours.

For more precise control of load and recovery there are specialized online platforms that automatically track your training stress balance, calorie and electrolyte expenditure, and adapt your nutrition plan to your metabolic profile. Such tools are especially useful when preparing for important races.

6.2. The “Litmus Test” of Your Health: Kidneys and pH

Intense training is a stress that “acidifies” the body. Our kidneys are tireless workers operating 24/7 to keep the acid-base balance (pH) in check. If we overload the system, the kidneys may struggle to keep up.

How do you monitor this? The simplest and surprisingly effective way is to watch the color of your urine. It should be a light straw color. If it's dark yellow, you're dehydrated and your kidneys are being forced to work in concentrated mode. If it's as clear as water, you may be drinking too much and washing out your salts. It's a simple “indicator” you always carry with you.

6.3. Hormones: Quiet Distress Signals

If you constantly feel tired and irritable, your libido has vanished and you sleep poorly, the problem may not be your character — it may be your hormones.

Relative Energy Deficiency in Sport (RED-S) is a condition where you burn considerably more calories than you consume. Like a prudent manager in a crisis, the body starts “cutting costs”: it reduces the production of hormones that are “non-essential” for survival, including the sex hormones.

In men, testosterone levels fall.
In women, the menstrual cycle becomes irregular or disappears entirely.

These are very alarming bells! They mean you're not just tired — you're in a state of deep energy deficit that leads to bone loss, injuries and depression. There is only one treatment: eat more (especially carbohydrates and fats) and train less.

6.4. Fat: A Friend, Not an Enemy

In a world obsessed with weight loss, we're used to treating fat as the enemy. But for an ultramarathoner, a certain percentage of body fat is a vital necessity.

It's energy — your main fuel tank.
It's hormones — adipose tissue takes part in the synthesis of many important hormones.
It's thermoregulation — it helps you retain heat.

The urge to get “shredded to the bone” before a race is a huge mistake. Sensible reference ranges for endurance athletes: men — roughly 8–15%, women — 16–24%. Essential (life-critical) fat is about 3–5% for men and 10–13% for women; you must not approach those values, let alone hold them: too low a body fat percentage is a direct route to hormonal disruption and RED-S. You can estimate your current percentage in the body fat calculator — using four methods, from the US Navy formula to a visual scale.

6.5. Playing With Altitude: How Not to Get “Mountain Sickness”

If your race takes place in the mountains, you'll have to deal with one more factor — altitude. Lack of oxygen is a serious stress.

There are two main acclimatization strategies:

Arrive well in advance (2–3 weeks early). Your body will have time to adapt, will produce more red blood cells, and at the start you'll feel almost at home. This is the ideal option, but sadly one rarely available to amateurs.
Arrive at the last moment (less than 48 hours before the start). The idea is to “slip past” the hardest period of adaptation, which usually hits on days 3–5. You start the race still running on your “old” lowland resources. It's a risky but workable “budget” strategy.

The worst thing you can do is arrive 3–4 days before the race. You'll land right in the middle of the acclimatization “pit.”

6.6. Recovery: When Progress Happens on the Couch

Here is a paradox that many beginners struggle to accept: you get stronger not during the workout, but during the rest that follows it. A workout is a stress that damages your muscles, depletes your energy stores and fatigues your nervous system. Recovery is the moment when the body “repairs itself,” ending up slightly stronger than it was before the session.

Neglecting recovery is like digging a hole and immediately filling it back in. You toil, but you don't progress.

Sleep: the royal recovery tool. Nothing is more powerful for recovery than quality sleep. It is during sleep that:

muscles are repaired;
growth hormone is synthesized;
the immune system is strengthened;
memory is consolidated (including muscle memory).

For an endurance athlete the minimum is 7–8 hours of sleep, and during heavy training blocks — 9 hours. If you sleep 5–6 hours, you are literally sabotaging your own progress. No gels or supplements can compensate for chronic sleep deprivation.

Active vs. passive recovery:

Passive — complete rest. Lying on the couch, reading a book, watching a series. Necessary after very hard workouts and races.
Active — light activity (a walk, a very easy run or bike ride in Zone 0, swimming, yoga). It helps get the blood moving, clear metabolic by-products and release muscle tension. Often more effective than complete rest, especially the day after a hard workout.

The golden rule: if you're unsure whether you need one more workout or a rest day, choose rest. It's better to arrive at the start line slightly undertrained but fresh than overtrained and worn out.

Recovery tools: what actually works.

Foam roller. A simple tool for myofascial release. 10–15 minutes of rolling after a workout helps release muscle tension. Does it work? Yes, moderately. Is it mandatory? No, but it's useful.
Compression garments. The evidence is weak: in a recent meta-analysis of endurance athletes, the shift in favor of compression for muscle soreness did not reach statistical significance, and effects on performance could not be pooled. There's no harm; if you subjectively like it — wear it.
Massage. A sports massage 1–2 times a month helps release the deep muscular knots you can't reach with a roller. Especially useful during heavy training periods. The massage should not be a relaxation massage but a proper sports one — deep, working the trigger points.
Cryotherapy (cold). Ice baths, cryo chambers. The scientific data are contradictory: cold reduces inflammation but may slow the muscles' adaptation to training. Use it wisely: right before an important race for quick recovery — yes; during the base training period — not necessary.

What does NOT work: most “detox procedures,” “energy bracelets” and “magic supplements.” The best recovery tools are free: sleep, proper nutrition and sensible load planning.

HRV: the “barometer” of your readiness. Heart rate variability (HRV) is a measure of how well your nervous system has recovered from training. It's measured in the morning, before getting out of bed, using dedicated apps and sensors.

High HRV — the body has recovered and is ready for load.
Low HRV — you haven't recovered yet. Better to do an easy session or take a full rest day.

HRV is not a mandatory tool, but for those prone to overtraining, or those who simply want to “digitize” their recovery, it's a very useful thing.

Red flags: when it's time to stop. Signs that you're close to overtraining:

constant fatigue, even after sleep;
morning resting heart rate 5–10 beats above your usual;
irritability, apathy, depressed mood;
frequent colds and infections (weakened immunity);
reluctance to train (not to be confused with laziness!);
a plateau or decline in results;
sleep disturbances (trouble falling asleep, shallow sleep);
loss of appetite.

If you observe 3–4 of these symptoms at the same time — that's an SOS. You need to reduce the load urgently or take a full week of rest.

📖 Case study: Maria, 35, trail runner

Maria was preparing for her third 100 km ultra. She had completed the previous two successfully. She had an ambitious goal — to improve her time by an hour. She took on a demanding training plan: 6 days a week, a weekly volume of 90–110 km, lots of tempo work.

For the first 8 weeks everything went brilliantly. Her results in benchmark workouts kept improving. But in week 10 strange things began:

she woke up feeling as if she hadn't slept at all;
her morning heart rate rose from the usual 52 to 64 beats;
on an easy run her heart rate was 150 at a pace where it used to be 135;
a constant urge to nap during the day;
she snapped at little things and quarreled with her husband.

“I'm probably just tired — I need to push through,” Maria decided, and continued the plan. A week later — a cold. Another week later — a nagging pain in her knee that wouldn't go away.

Diagnosis: overtraining. Her body couldn't recover between the hard blocks.

Solution:

a complete stop to training for 10 days;
blood tests showed low ferritin (iron stores) and a vitamin D deficiency;
after recovery — a revised plan: a proper full day off added, volume reduced by 20%.

Result: after 3 weeks of rest and easy training her morning heart rate returned to 52, her sleep normalized, and her knee stopped hurting. The race had to be postponed by 2 months, but she finished it healthy.

The lesson: red flags must not be ignored. Your body doesn't lie. If your morning heart rate is up, your sleep is disturbed and you're constantly tired — this is not a case of “push through,” it's a signal to STOP. Better to miss 2 weeks of training than to drop out for 3 months with an injury or illness.

Periodizing your rest. Plan your recovery as carefully as your load:

Microcycle (a week): after 2–3 hard sessions — 1–2 easy days or a rest day.
Mesocycle (a month): after 3 weeks of loading — 1 recovery week (volume reduced by 30–50%).
Macrocycle (a year): after the season ends — 2–4 weeks of complete rest from running or minimal activity.

Remember: “rest” is not weakness. It's the strategy of the smart and the strong.

6.7. Key Nutrients for Ultramarathoners: What Runners Are Missing

Ultramarathoners are machines for burning calories and sweating out minerals. Even on a balanced diet you can develop deficiencies in key nutrients that slow your progress, impair recovery and increase the risk of injuries and illness.

Magnesium: the quiet shortfall of the majority. Magnesium is involved in 300+ biochemical reactions: energy metabolism, muscle contractions, protein synthesis, nervous system function. According to national dietary surveys, about half of adults fall short of the magnesium norm through food; clinical deficiency is rarer, but athletes are at higher risk because of sweat losses.

Symptoms of a shortfall: muscle cramps (especially at night), poor recovery, sleep problems, chronic fatigue, anxiety.

What to do: the norm for an athlete is 400–500 mg/day. Magnesium citrate or glycinate is absorbed better (oxide is absorbed poorly). Food sources: nuts, seeds, dark chocolate, spinach, bananas.

Iron: especially important for women. Iron is needed for oxygen transport (hemoglobin) and cellular energy metabolism. Iron deficiency means chronic fatigue, a drop in performance, shortness of breath. Women's risk of deficiency is 3–4 times higher because of menstruation. Vegans and vegetarians are also at elevated risk.

Symptoms: constant fatigue even with good sleep, declining results at the same training load, elevated heart rate at familiar paces, pallor, brittle nails.

What to do: get a ferritin test (iron stores). The norm for an athlete: 50–100+ ng/ml (don't confuse it with hemoglobin!). If ferritin is <30 — you have a deficiency. Sources: red meat, liver, seafood. For vegans — iron supplements + vitamin C for better absorption.

Vitamin D: the “sunshine hormone” for immunity and bones. Vitamin D is actually a hormone. It is critically important for immunity (fewer colds), bone health (prevention of stress fractures) and muscle function. The problem: 40–60% of the population is deficient, especially at northern latitudes in winter.

Symptoms: frequent colds and infections, bone and muscle pain, low mood (especially in winter).

What to do: get a 25-OH vitamin D test. The optimum for an athlete: 40–60 ng/ml (100–150 nmol/L). If it's below 30 — take supplements: 2000–4000 IU/day. Food sources: fatty fish, eggs, mushrooms. The best source is the sun (15–20 minutes outdoors in summer).

Omega-3 (EPA and DHA): the inflammation fighters. Long, intense workouts cause systemic inflammation. Omega-3 fatty acids help reduce inflammation, speed up recovery, improve heart function and support the joints.

What to do: eat fatty fish 2–3 times a week (salmon, sardines, mackerel). If you're vegan or don't like fish — take supplements: 1–2 g of EPA+DHA per day. Flaxseed oil doesn't count — the body converts ALA into EPA/DHA poorly.

Sodium in everyday life. We're used to thinking that “salt is evil,” but for an endurance athlete it's more nuanced. The WHO's baseline recommendation for the general population is up to 2 g of sodium per day (5 g of salt), and for rest days it's reasonable. But on days with long, heavily sweaty training sessions you lose an additional 1–3 g of sodium or more through sweat — those losses need to be replaced on top of the baseline, so don't be shy about salting your food. A simple guideline: the more white streaks on your shirt after training and the stronger your craving for salty food — the more you should add.

How to check for deficiencies. Don't guess. Get blood tests 1–2 times a year:

a complete blood count (hemoglobin, red blood cells);
ferritin (iron stores);
25-OH vitamin D;
magnesium (better measured in red blood cells, not plasma);
thyroid hormones (TSH, T3, T4).

If you have chronic fatigue, declining results or frequent illness — go to a doctor and get checked.

What you do NOT need: most multivitamins, “sports complexes” and dietary supplements are marketing. The exception: nutrients where a deficiency has been confirmed (magnesium, vitamin D, omega-3, iron when necessary).

In the next part of the book we'll move on to the tastiest topic — race strategy. We'll talk about what, how much and when to eat and drink to reach the finish with a smile rather than an IV drip.