Exercise while fasting: What activity is right for your fasting week

The essentials at a glance

• Exercise has always been an element of the Buchinger fasting therapy, provided it is dosed moderately and performed at a calm pace.
• Moderate endurance and strength training are suitable, complemented by yoga, Feldenkrais, Tai Chi, resistance band training, and breathwork.
• Hiking and summit tours remain possible, just at a slower pace than in your everyday life – the body is nourishing itself from within.
• Studies show that strength is largely maintained during fasting, while peak endurance performance decreases – a good reason to dial back the pace.
• At the Naturhotel Tannerhof, a medically supervised endurance and strength fitness area, an outdoor natural pool, and the BadeHarpfe are available for your use.

Why exercise is part of fasting

When people think of fasting, they first think of silence, a morning herbal tea, and a sweeping view of the valley. Nevertheless, exercise is an essential part of it from the very beginning. Otto Buchinger himself combined abstinence with movement, fresh air, and warmth – not as an add-on, but as an integral part of the method. Buchinger therapeutic fasting is the conscious, time-limited abstinence from solid food and stimulants, and during this time, the body should not be shut down, but rather kept in a calm rhythm.

At Naturhotel Tannerhof, therapeutic fasting has been medically supervised for over 70 years, and exercise is an integral part of it. The therapeutic fasting guidelines, published by the Medical Association for Therapeutic Fasting and Nutrition (ÄGHE), include outdoor physical activity as an essential component of treatment. Those wishing to explore the specific program details at our retreat and book online can find them in the Body Detox program, the medically supervised therapeutic fasting retreat at Tannerhof.

Exercise during fasting does not mean training against the body, but with it. It keeps the circulation active, supports the metabolism during the transition, and gives the day structure. Above all, however, it changes your experience: a walk through the alpine meadow, a few calm breaths in the open air, a stroll along the mountain stream – these are not training sessions, but part of the fasting experience. The question is therefore less about whether you exercise, but rather how and to what extent.

What pace is suitable for fasting

The principle is simple: moderate rather than maximal. During fasting, the metabolism switches to fat burning; glucose levels drop, and fatty acids and ketone bodies take over. This transition is described as a central mechanism of fasting in the review by de Cabo and Mattson in the New England Journal of Medicine (2019), as well as in the ÄGHE guidelines. For exercise, this means that short-term, rapidly available energy reserves are more limited. Those who take this into account will start at a slower pace – and that is exactly how they will get through the week successfully.

A recent study has described in more detail how the body reacts to exertion during fasting. Research by Kolnes et al. (Nature Communications, 2025) monitored healthy adults over seven days of fasting and tested their strength and endurance. The result fits well with the Tannerhof practice: muscle strength in the legs remained largely intact throughout the fasting week, while maximum endurance performance – peak oxygen uptake – decreased by about 13 percent. In other words: strength is sustainable, while high endurance peaks are less so. This is not a deficiency, but a sensible adaptation. The body saves its quick reserves and lives from within.

From this stems the Tannerhof philosophy, which can be summed up in a single sentence: a fasting week is no time for setting personal athletic bests. If you usually run for time, slow your pace. If you collect summits, take them at a tranquil stride. Moderation is guided by the fast, not by ambition. The body draws nourishment from within—and it is precisely this principle that guides every movement throughout the week.

Endurance and strength – moderately dosed

Two pillars support exercise during fasting, both consciously kept in a moderate form.

• Moderate base endurance training. Walking, leisurely hiking, gentle cycling, or swimming laps—activities where you can still hold a conversation and your breathing remains calm. This foundational work aligns naturally with the fat burning of fasting, as it draws directly on the energy reserves your body is actively tapping into.
• Moderate strength training. Gentle, controlled exercises using body weight, resistance bands, or light weights that engage muscles and joints without overwhelming them. Because muscular strength is largely preserved during fasting, you can work out calmly yet effectively.

Both find a home at the Tannerhof: In the endurance and strength fitness area of the BadeHarpfe, both can be dosed in moderation, with a view of the outdoors rather than a mirror. The pace remains important. It is not about setting a training stimulus or building muscle, but about keeping the body in motion and supporting the transition. If you wish, you can have the medical team tailor the appropriate level to your needs – every fasting day is different, and every person starts from a different point.

Yoga, Feldenkrais, Tai Chi, and Breathwork

In addition to endurance and strength, subtle, slow movement has special value during fasting. It connects the body and the mind, keeps you flexible, and provides calm – and it suits days when the body receives little, but the senses receive more.

• Yoga, practiced gently, stretches, opens the body, and brings your breath into a steady, rhythmic flow.
• Feldenkrais cultivates subtle, mindful movement patterns and sharpens your awareness of your own body.
• Tai Chi guides you through slow, flowing sequences that foster balance and concentration.
• Resistance band training builds strength while protecting your joints and allows for precisely tailored intensity.
• Breathwork works with the gentlest tool of all, deepening the inner stillness of your fasting week.

These forms of exercise are part of the broad spectrum of therapies and treatments at Tannerhof, which during fasting extends far beyond physical activity: medical history and examination including bioimpedance analysis, medical follow-ups and final consultations, IHHT altitude training depending on the program, Kneipp hydrotherapy, hay flower and aromatic body wraps, fasting massages, detoxifying massages with herbal oil or acidosis massages, and breathwork. An overview of our therapies and treatments can be found in our treatment offerings. On the mental and emotional level, Tannerhof also offers psychotherapeutic coaching, nature coaching, business and communication coaching, and art therapy.

Hiking and summit tours at a fasting-friendly pace

In the mountains, movement happens almost by itself. You walk across alpine meadows, along mountain streams, up to the next ridge – and the path sets the pace, not ambition. Walking sorts your thoughts, brings your breath into a rhythm, and leads you through a landscape that helps you slow down instead of working against it.

Hikes and summit tours are still very much possible during a fasting week. They simply unfold more slowly than in daily life, with more rests and fewer vertical meters in a single stretch. Those who embrace this pace often experience the mountains far more intensely, as taking in the views is given time and space. If you wish to focus specifically on walking while fasting, our combination of Buchinger fasting and guided mountain hikes offers a dedicated program—learn more on our Hiking and Fasting page. For everyone else, the trails right on our doorstep are plenty: Tannerhof is set on around 16 hectares of private grounds, connecting directly to trails around Bayrischzell with expansive views of Mount Wendelstein.

The only thing that matters is that your walking follows the rhythm of your fasting day. On an easy day, you can go further; on a quieter day, a short loop is enough. The mountains aren't going anywhere, and that is exactly the point: during your fasting week, everything is fundamentally fine, just slower.

Water, warmth, and mountain views

At Tannerhof, movement also embraces the element of water. Opened in 2025, the BadeHarpfe combines a Finnish sauna, a panoramic relaxation lounge, a cardio and strength fitness area, and a natural outdoor pool. Measuring 25 by 5 meters, the stainless-steel pool is naturally filtered and heated from April to October; in winter, it becomes an ice-swimming pool. Looking out between Mount Wendelstein and Sonnwendjoch, a swim with a mountain backdrop becomes a quiet daily highlight during a fasting week. A few gentle laps are moderate endurance training at its finest: steady, buoyant, and free from competitive pressure. Sweat, smile, plunge.

This is how movement and rest come together. A round in the pool, a lap under the open sky, followed by the warmth of the sauna and the expansive view from the panoramic relaxation room. What comes after the movement is no less important than the movement itself. Those who fast learn to appreciate this alternation anew: walking and observing, moving and finding rest, challenging the body and giving it time.

Movement, medical support, and landscape

At the Tannerhof, three things belong together: the method, the medical support, and the landscape. The method provides structure, the medical team provides safety and individual direction, and the mountains provide perspective. None is more important than the other. Fasting in a moving landscape is significantly more intense – and a moving landscape only unfolds its full depth with expert guidance.

This is especially true for physical activity. The right level for any given day can be easily coordinated with our medical team. The doctors at Tannerhof are experts in fasting; they monitor your vital signs and circulation as well as your individual progress. The initial consultation on your first day of fasting is holistic: it includes a medical history, a physical examination with bioimpedance analysis, and a medication review. We also discuss why you are fasting, your goals at Tannerhof beyond the fast, and your previous fasting experience. This provides a clear picture of how much exercise is right for you. Your length of stay is booked before arrival; from the initial consultation onwards, the duration and schedule can be adjusted, such as extended, in coordination with our doctors.

In this way, exercise during a fasting week leaves behind far more than just a count of steps. It leaves a lasting bodily memory: how good walking feels, how clear the mind becomes after a quiet stroll, and how little we sometimes need. Perhaps that is the timeless Tannerhof ethos in its contemporary form: Return to what truly matters.

Physical activity while fasting at Tannerhof

If you are looking to stay active while fasting, Naturhotel Tannerhof offers just the right balance: moderate base endurance training and moderate strength training, yoga, Feldenkrais, Tai Chi, resistance band workouts, and breathwork, alongside hikes at a fasting-friendly pace, the cardio and strength fitness area, and the BadeHarpfe natural outdoor pool. Find full details on the program and book online under Body Detox, and discover more about combining walking with fasting under Hiking and Fasting.

Note: This article describes the approach and practice of the Tannerhof nature hotel regarding physical activity during fasting. It does not replace individual medical advice. A preliminary medical consultation by phone is available upon request.