Imagine this scene: 5:30 in the morning, the alarm rings, and a gentle tug-of-war stirs within. One part of you leans toward the phone and the comfort of five more minutes under the blanket. Another part recalls the practice or the work that holds meaning for you. No adversary stands in this moment, just a choice as old as the tension between comfort and purpose.

In the Katha Upanishad, these two pulls are named: one as preyas, short-term comfort, and the other shreyas, long-term meaningful fulfilment. Both present themselves to us, and wisdom lies in choosing what endures. Yoga calls this choice: tapas. Although often rendered as austerity or penance, tapas here points to choosing what endures over what merely entices, the sustainable over the passing. The Yoga Sutras place tapas at the very centre of the yoga of action (2.1).

Neuroscience, of course, approaches this issue differently. Rather than asking what the choice means, it asks how we make the choice. The most illuminating account is perhaps one which brings both of these together: one in the language of values, one in the language of mechanisms.

The friction is a signal

That inner tug-of-war is not a sign of failure. When two responses compete, the anterior cingulate cortex (ACC) detects the conflict and signals that more control is needed. The anterior insula is the bit that takes the signals coming in from the body and weaves them into a sense of the present moment. Awareness is where the choice occurs.

The brain then starts to weigh things up. In a 2004 brain imaging study, the options available at that very moment elicited increased activity in the reward centres (the ventral striatum in particular) as if the present moment was somehow more valuable. The lateral prefrontal cortex was active for every choice, and the more active it was, the more likely the participant was to choose the bigger, delayed reward. It's not a story of a bad system against a good system. Sometimes an immediate reward is the sensible choice, and it's perfectly acceptable to rest when you're tired.

Not willpower, but worth

The ACC also appears to be making a rather more subtle calculation: is the effort worth it? Because effort feels costly, the brain likely invests when the reward is high and the effort matters. Experimental evidence shows people put in more effort when the stakes are higher and their actions actually make a difference. Maybe discipline has less to do with sheer determination and more to do with keeping what really matters in view.

This may also help explain why so many 'all or nothing' diets end in failure. In classic studies, dieters who thought they'd already broken their diet ended up eating more, not less; once you've broken the rule, it can feel completely lost. A Tapas regime of a fixed duration (a few weeks rather than for life) can avoid that trap. It offers a tangible finish line with a reward close enough to the 'now' to be competitive, and each completed phase proves effort can work, which in turn makes the next start a little easier.

Not all effort is the same. The Bhagavad Gita speaks of three types of tapas: tamasic, born of confusion and self-torture; rajasic, undertaken for recognition and inherently unstable; and sattvic, offered with faith and without desire for the fruits of action. Neuroscience can measure effort, but it can't tell you what it is for. That may be the province of wisdom.

Something gets stronger

In a 2010 study, just a month of meditation training (some 11 hours in total) resulted in increased connectivity in the ACC as compared to relaxation training. A very short time commitment, yet a real and measurable difference. Reviews of the mindfulness literature describe a process that starts as effortful doing and, as you go on, becomes increasingly effortless being. The Gita describes the same trajectory: sattvic happiness may feel bitter at first and then sweet later. What you choose again and again becomes easier, and something within you seems to grow.

Progress is rarely linear. Sleep, stress, and grief can all tip the balance, and that's just biology. It's not a sign of failure.

Context can also tip the balance. A craving, a phone glowing on the pillow, a restless mood, or a sleepless night can all strengthen the pull of the present or weaken prefrontal control. The ancient yogic advice to guard the senses seems to echo in modern neuroscience.

Chosen again and again, the good that endures becomes easier to choose and something in us grows stronger.

What neuroscience can't tell

Tapas is not simply ACC activation. The same regions activate whether we choose wisely or chase vanity, and a way of life is bigger than any brain region. Yet the two vocabularies, two thousand years apart, point to something similar.

Maharishi Patanjali puts it in a single line:

कायेन्द्रियसिद्धिरशुद्धिक्षयात्तपसः

kāyendriyasiddhir aśuddhikṣayāt tapasaḥ (Yoga Sutras 2.43)

Through tapas, impurities decrease, and the body and the senses are perfected.

When we apply heat steadily, the instrument through which we meet the world gradually becomes clearer.

Perhaps it's just a small daily question: what is one thing I can do today that helps me become the person I want to be? Ten minutes of focused work, one honest sentence, or simply rest rather than scroll.

The heat is very real and so is our capacity to learn how to carry it with wisdom.