Hola
Here are some advices regarding sleeping bags:
• Use an inner silk or fleece liner/bag.
A silk liner adds about 5° degree celsius to the bag and a fleece 8°.
On winter camping/trekking two liners are often used as the effect adds up and the liners are light weight.
• The sleeping bag does not make you warm.
It function as a thermo and isolate you.
This mean that it contains the warmth/heat you put in, so make some gymnastic before you enter and you will sleep warmer.
Think of the difference of pouring cold or hot water into a thermo.
• Wear a beanie, scarf, long johns, gloves, cloth while sleeping.
• Unpack your sleeping bag early before going to sleep as the down/synthetic needs to unfold to provide maximum insulation.
• Ventilate you sleeping bag in the morning to get rid of sweat before packing it up.
• Do use a sleeping bag that matches your size. A to large result in to much air that needs to be heated and a to small result in to little air to provide best insulation.
• Put some hot water in your 0.5 liter water bottle and bring it into the sleeping bag.
• Never go hungry to bed. Energy equals heat.
• Remember to go to bathroom and pee off before going to bed.
The body uses a huge amount of energy if you are in a state that needs to go to the bathroom.
Buen Camino
Lettinggo