GR20 in 7 days

I have never been before on a trail like the GR 20. The plan was to start in Conca on June 28 and end in Calvi 7 days later. Trying to make this hike within 7 days seemed ambitious to me.

Unfortunately, my tour ended at the Refuge de Manganu. When the Guardian saw that huge thing on my right heel he just said:"Pour toi, c'est fini!".


For reference, see the map below.

A: Starting point, Conca, Gite "La Tonnelle"
B: Refuge de Asinau
C: Refuge de Prati
D: Vizzavona, end of GR20 south
E: Refuge de Petra Piana
F: Refuge de Manganau, premature end
G: Soccia, exit

Later I learned that I also had picked up bedbugs. These little bastards had been quite nasty as the wounds they had left behind went septic. Getting rid of that was some fun, too.

Day 1: La Tonnelle to Asinau

Energy use:8100 kcal
Avrg Heartbeat125/min
Time:La Tonnelle -> Refuge Paliri: 5h
Refuge Paliri -> Refuge Asinau (alpine route): 6h50
Time lost:

30min searching path
30min taking baths


Alpine route, Bavella Massiv: avoid green marked path, follow yellow marked path instead

Shoes used:heavy boots

Day 7: Calvi

Early in the morning I picked up the rental car and drove to Calvi where I first visited the Antenne Medical. They opened the blister which at meanwhile had become bloody.

Day 2: Asinau to Prati

Energy use:7700 kcal
Avrg heartbeat120/min
Time:Refuge Asinau -> Refuge Usciolu: 7h
Refuge Usciolu -> Refuge Prati: 5h10
Time lost:

20min searching path

Pitfalls:On top of Monte Inducine the GR20 has been redirected to the north-west to lead walkers to the Bergerie de Croci. This is a detour unless a stay there is planned. If not, the yellow markings to the north-east take walkers on the old GR20.
Remarks:Time consuming passages downhill from Monte Inducine and on the following ridges to Refuge d'Usciolu and to Refuge de Prati.
At Prati, two like bandits looking Corsicans will await you. These two guys are really refreshing. I liked them a lot.
Shoes used:Heavy boots

Day 3: Prati to La Foce (Vizzavona)

Energy use:5100 kcal
Avrg heartbeat110/min
Time:Refuge Prati -> Refuge La Capannelle: 5h05
Refuge La Capannelle -> Hotel Monte d'Oro: 4h50
Time lost:

50min break @ La Capannelle, problems with both big toes.


Hiker's highway. A lot of it could be run. This is the longest double etappe on the southern GR20.
2 tiny blisters on the right heel. A Compeed should do the trick.

Shoes used:To La Capanelle I used heavy boots. From there, I used running shoes to relieve the big toes.

Day 4: La Foce to Petra Piana

Energy use:4700kcal
Avrg heartbeat115/min
Time:Hotel Monte d'Oro -> Refuge de l'Onda: 4h30
Refuge de l'Onda -> Refuge Petra Piana (alpine route): 3h40
Time lost:


Remarks:Easy going way between the Hotel and Refuge de l'Onda. Quite some scrambling between Refuge de l'Onda and Refuge de Petra Piana if taking the alpine route. Avoid low route. Last climb is more than 900 meters.
The 2 tiny blisters on the right heel have grown to one huge blister. Forced stop @Petra Piana.
Shoes used:Running shoes (watch your step!)

Day 5: Trying to fix the unfixable

The blister on the right heel turned out to becoming a real threat to finishing GR20. A very nice doctor from Poland fixed me up as good as possible but it was already too late. She suggested to exit GR20 or at least to make a long break. 
Thanks for everything, Anna.

Day 6: Petra Piana to Ajaccio via Soccia

Energy use:4100 kcal, stop of measurement @Manganu
Avrg heartbeat108/min, stop of measurement @Manganu
Time:Refuge Petra Piana -> Refuge Manganu : 5h30
Refuge Manganu-> Soccia (exit): 2h30
Time lost:1.5 hours, snail pace
Remarks:The way to Refuge de Manganu is fast and can be done in 4h30. The Breche de Capitello is easy.
Shoes used:Heavy boots

Lessons Learned

Fully loaded, my rucksack was 14kg. I had one t-shirt and a lot of food in excess. Also, the heavy boots and my running shoes could have been combined to light trekking shoes. I sprained both my ankles a couple of times in the heavy boots but never in the running shoes although a lot of the way is full of rocks.
Food supplies are perfect in the Refuges. They have everything. Taking along more than one day of food supplies is overkill. However, the food they offer is good enough for hikers that do the GR20 in 14 days but it's not nearly sufficient to cover the energy consumption I experienced. Next time I'd go for food that is small, very low in weight, has 3 times the energy of 100g chocolate and does not go to waste in any kind of climate. If this existed, I'd be the first to buy.
3 liters of water are plenty even on hot July days. On the southern GR 20 there are enough springs and other possibilities to refill.
Properly managed, the total weight of the rucksack can be kept under 10kg without losing any minimal comfort.

Physcial damage to feet, such as blisters, are a big problem and need to be prevented, not repaired. Tape,  Compeed and small scissors or a knife should have been part of the kit. I had Compeed with me but it did not at all solve blister problems. Also, bed bugs should be expected.

Also, I had underestimated the roughness of the terrain. This is what really slows down. I got the impression that doing 3km/h in distance was already good. Often, going uphill often seemed easier and faster than the opposite.

I definitely learned to eat. Days can be quite energy consuming. It is important to keep energy levels high. The alternative means rapid loss of strength and determination. Never let hunger come up.