You can trek early everywhere in Nepal. You can trek alone, with a porter and/or with a guide. With a guide you can benefit from his trekking experience and his knowledge of geography, fauna, flora, culture... A porter will take the pain out of a heavy load and you will fully enjoy your trek.
As mentioned above you can trek everywhere in Nepal but there are few restricted areas which require a special permit, sometimes being 2 trekkers, sometimes a guide: upper and lower Dolpo, lower and upper Mustang, Gorkha regions, Nar and Phu, Gaurishankar and Lamabagar, Thuman and Timure, Simikot and Yari, Sankhuwasabha, Kanchanjanga region, areas of Kanda, Saipal and Dhuli...
Some areas require a special entry permit:
- Sagarmatha National Park
- Chitwan National Park
- Langtang National Park
- Bardiya National Park
- Khaptad National Park
- Makalu / Barun National Park
- Rara National Park
- Sheyphoksundo National Park (Dolpo)
- Shivapuri Nagarjun National Park
- Koshi Tappu Wildlife Reserve
- Parsa Wildlife Reserve
- Sukla Phanta Wildlife Reserve
In general good warm clothing such as down jacket, thermal undergarment, good trekking shoes, wind proof trousers, torch, scarf, hat, sunglasses, warm socks, sun cream, lip balm and trekking poles to assist with trekking at times. Lodges are often very cold, only the dining room has sometimes a wood stove. Above 3500 m a good sleeping bad is required (-15°C even less).
Accute Mountain Sickness
Altitude sickness is a disorder caused by being at high altitude where there is less oxygen. It more commonly occurs above 8000 feet or 2440 metres. It is difficult to determine who may be affected by altitude sickness since there are no specific factors. More, one time you can be affected and another time not affected.
The main cause of altitude sickness is ascending too high too quickly. The number of oxygen molecules per breath is reduced as altitude increases. At 3600 metres there are roughly 40% fewer oxygen molecules per breath compared to at sea level. Also, the lower air pressure at high elevation can cause fluids to leak from the capillaries in the lungs and the brain, which can lead to a fluid build-up. Your body needs to adapt to the decrease in oxygen at a specific altitude. This process is known as acclimatization and generally takes one to three days at a specific altitude. Without proper acclimatization, it can lead to potentially serious, even life threatening altitude sickness.
There are three types of altitude sickness:
1- Acute Mountain Sickness (AMS). This is the effect of altitude on those who ascend too rapidly to elevation beyond 3000 metres. Any of the following symptoms must alert you: headache which persists with medicine, lost of appetite or sleep, nausea, vomiting, dizziness, shortness of breath at rest, abnormal fatigue, decrease in the amount of urine... Depending on how you cumulate these symptoms, you must climb more slowly, stay at the same altitude or descend immediatly. For more information have a look to the Astruc scale.
2- High Altitude Pulmonary Edema (HAPE). This is a dangerous build-up of fluid in the lungs preventing the air spaces from opening up and filling with fresh air with each breath. Symptoms include water in lungs, increasing shortness of breath even at rest, severe cough - dry/productive, unusual fatigue while walking, high pulse rate, and blueness of face, lip, fingernails which indicate the inability of transporting oxygen into the blood.
3- High Altitude Cerebral Edema (HACE). This is the result of swelling of brain tissues from fluid leakage. Symptoms include water in the head, severe headache, vomiting, walking like intoxicated, mental confusion or altered mental status, irritable and easily annoyed, and unconsciousness or coma.
For the best altitude acclimatization this is very important to follow the recommanded acclimatization ascent rates. This means that the altitude of 3000 m should be reached in 3 days and that 2 consecutive nights must be spent at this altitude. Then an average of +350 m per day is recommended until the altitude of 4000 m where you should spend again 2 consecutive nights. Then from 4000 m to 5000 m the average of +350 m per day should be respected again.
Some other rules shall help for a good acclimatization: drink more than usual to compensate the dry air ; every day climb 300 m higher than the altitude you will sleep, stay a while then descend for sleeping ; do not drink alcohol.