Takeaways from this article:

• Identify how base training fits into your seasonality and race preparation, and structure accordingly to fit individual goals.

• Use this time to experiment and develop dietary habits that can become second nature during race season. Consider nutrient-dense options, consistency and balance, and gut-friendly pre-training meals.

• Scale carbohydrate intake to match individual session intensity, utilize intentional within-session fueling with sports nutrition to support higher demands.

• Get into the habit of keeping a fuel diary and monitor how the body responds.

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The focus of any training period is determined by an athlete’s race goals. The intention is to use the right combination of training methods to develop the necessary physical adaptations that enable an athlete to arrive at the start line in a peaked physical state. Base training encompasses a range of training practices and although there is broad agreement for the purpose of base training, there is no established rule of what works best. The scientific community acknowledge that, to improve, to produce strong performance at threshold (or above), it’s a prerequisite to have first built a solid base foundation that acts as a launchpad for the next phase of training. How an athlete chooses to structure their base training will depend on the type of race, the sport, personal training preference, and personal circumstance and lifestyle.

Although it can be practiced at any time (depending on race schedules), base training is most often deployed during winter. At this time, racing may now be out of sight — several flips of the calendar away — but not out of mind. It’s still a training period that’s dictated by purpose and requires both structure and discipline. Fueling during this period should not be neglected — it matters and should be tailored to the revised training demands.   

Like all aspects of training and racing, the details and specificity are personal. Perception of intensity and duration are different from one athlete to the next. It’s up to you, the athlete, to define your own interpretations of what these mean. This is another moment to reinforce the importance of a personal approach to training and fueling. Don’t be tempted to follow the example of others and always work within your means. Even during a period of higher volume and lower intensity it’s possible to over-reach and stray into a depleted state that would negatively impact future training performance.

It's also important to make the distinction between base training and the historical understanding of winter training. The traditional approach of winter training was to build a strong foundation of base fitness by undertaking a sustained period of long, low-intensity work with very little spiking of effort. The efficacy of this practice is heavily dependent on time — it requires many hours of low intensity to be effective. Something well-suited to the lifestyle of a professional athlete but less so for the everyday amateur. With limited time, focusing on low intensity is unlikely to provide the training stimulus that enables the body to adapt. Adaptation requires an athlete to stress the body in different ways, through a variety of sessions.

There are two primary approaches to base training.


Linear Periodisation consists of predominantly longer, easy-to-moderate training (conditioning) that aims to build a strong aerobic base and is closer to the traditional interpretation of base training. Typically, this starts with more volume and reduced emphasis on high-intensity sessions. As the training phase progresses, more intensity is built into the plan — intervals, fartlek, or hill training — and duration reduces. Funnel Periodization is a modern variation of base training protocol. In this block of training, the athlete trends towards specificity as the goal race approaches. In other words, training becomes more focused on the target pace and conditions that will be experienced in the race. Both high and low intensity are prioritized in this training model and funnel towards each other so that, towards the end of the phase, all training is specifically aligned to the race.

Fueling during a period of base training matters and should be tailored to the revised training demands, whether Linear or Funnel in its planning. Fundamentally, this is the base of the pyramid — like laying the foundations. In sessions with a relatively low target heart rate, where the effort may be described as conversational, the demand for high-carbohydrate intake is reduced. As Lauren Thomas, Maurten Performance Nutritionist explains, “When exercising at under 65% of Vo2 maximum, the body is able to utilize oxygen more efficiently and fat will become the primary source of energy.” With in-session carbohydrate demand falling, be diligent about what you eat before and after. Lean into real food options as the predominant source of fuel with less need for high-carbohydrate supplementation in-session. Glycogen stores should be saturated before starting training.  

The seasonality of training requires an understanding of how to adapt in-session fueling to suit the demands of that period in the cycle. Between sessions, it’s unlikely that your everyday diet will need to change significantly to compensate for base training. Fueling with a varied and real food diet around training should be sufficient to provide not only energy, but also important nutrients and minerals, including sodium. 
 A period of sustained base training is a good opportunity to develop a routine that prioritizes a food-first approach. Outside of high-intensity training or racing, it’s easier to experiment with healthy, nutrient-rich foods that you get pleasure from preparing and eating. Building a positive mindset that enables a habit of choosing real food is important. Naturally occurring vitamins and minerals from whole food options will help to build resilience and strength, which are important attributes for maintaining momentum during the colder months. Just like a fueling strategy, food choices are personal and dictated by taste or preference. Learn what ‘gut-friendly’ means to you during the off-season so that you already know which foods are comfortable and effective when racing starts again. Keeping a food diary can help keep check of what is working.

Consistency and balance rule here. The sensations of long and slow training sessions can feel vague. You perhaps won’t get the same rush of satisfaction — or even reward — compared to hard interval sessions when the heart rate will be close to max effort, but it’s important to maintain structure and framework around eating. The fundamentals are simple — no skipping meals and maintain intentional, balanced snacking. It’s basic discipline. Longer training sessions won’t necessarily mean that you need to increase your portions or frequency. Whether you commit to Linear or Funnel Periodisation, or something else, base training is unlikely to be all about ‘long and low’. You will still be doing regular high-intensity training — to keep the blade sharp and assist adaptations. Remember that sports fuels are specifically designed to reduce the workload on your digestive system during high-intensity training, when blood is diverted to working muscles. In these specific sessions it’s appropriate to continue using high-carbohydrate fuel, even though the frequency will be less in an average base training week. 

Introduce in-session fueling for lower intensity base training that is longer than 1 hour, but keep it towards the lower end of what you can tolerate — 30-60 grams of carbohydrates per hour. With greater availability of blood in the gut when exercising at lower intensity, this could also be an opportunity to experiment with solid fueling options. Getting used to consuming textured fuel while exercising could be a valuable learning milestone if you plan to compete in longer endurance events.