As with all of the Niyamas or inner observances, practicing Tapas can look radically different from person to person. What is a struggle for one person comes easily to another. In her book The Yamas & Niyamas: Exploring Yoga's Ethical Practice, Deborah Adele uses the analogy of fire or heat to explain Tapas. She says, "Tapas is the day to day choice to burn non-supportive habits of the body and mind, choosing to forsake momentary pleasures for future rewards."
A person on a strict diet exercises Tapas each time he passes up an extra helping or goes without a dessert. A person saving up for something special demonstrates Tapas when she goes without to set aside the money she needs for her goal. The principle of self-discipline is broad. For instance, today it may look like limiting myself to one piece of chocolate when I want to have the whole bar; tomorrow it could be stepping onto my yoga mat after work when I would rather sit and relax. While neither option is right or wrong, making the conscious choice in one direction is the discipline.
Personally, this is a practice that I focus on daily. Unfortunately, I have a strong penchant for sweets. I gravitate toward desserts, fruits, and dark chocolate. However, I choose to eat a variety of foods, especially vegetables and leafy greens because they are good for me and long-term health is my goal. I also use the mantra "food is my fuel, not my friend" and mindfulness when eating to help me maintain self-discipline around food.
What is your daily struggle? Do you have an area in your life that requires more self-discipline? From over-consumption of food to over spending, from the tendency to be unproductive to the inability to set personal boundaries, we are all refining ourselves daily. Every time we make the choice to continue when challenged, to carry on when we feel defeated, or to persevere when we have fallen short of our goals, we are in the "fire" of Tapas.
As discernment increases, our struggle in that particular area may decrease. Around every corner of our lives, there is a new struggle. A new goal. A new focal point for our self-discipline. We are like the rough sea glass that is smoothed by the pounding water of the ocean. It is through the waves of life that we polish our own rough edges and lose the jagged parts of ourselves. And, as we are polished by our persistence, we will become the best version of ourselves to date.