A well working immune system according to Ayurveda depends from the strenght of our digestive fire, agni. Especially during mid March until mid June the Kapha dosha is dominant and in cool and wet weather produces cold, letargic tendencies in body and mind. The accumulation of mucus in the body caused hereby leads to stiff joints, low digestion, headache and tiredness.
In order to increase our energy during this period we should take care to not neglect the following in our everyday life:
-light meals and regular exercise
-fresh food, more spices, wholegrain products, organic vegetables and fruits, light dairy products such as ghee, lassi and fresh yoghurt, green vegetables and soups spiced with Kapha Churna (http://www.indiacurry.com/ayurveda/kaphabalancingchuran.htm)
-avoid foods, which load the body (industrially manufactured products, frozen and canned foods, remainders of another day, fast food and chemically grown food)