When clients share their fitness goals and progress, I often notice a recurring theme of self-sabotage. The initial surge of motivation leads them to dive headfirst into intense training, driven by the belief that exhaustion equals success. Intense training makes us feel exhausted and so the feedback loop feels like we are doing it right. Unfortunately, this approach often neglects basic endurance training principles, resulting in fatigue and, in some cases, regression rather than progress.

The Base Training Period may feel counterintuitive, as it doesn’t involve the same soreness and exhaustion associated with intense workouts. However, when you understand the principles behind it and commit to following them, you’ll see results much faster. So let’s dive into the theory and practice of base training, tailored specifically for those new to exercise.

Training measurements like these are common, yet lead to overtraining instead of improvement


Training for any physical goal or competition requires a well-structured training cycle, consisting of four key periods: the Base Period, Build Period, Peak Period, and Taper & Rest Period. In the Base Period, the athlete develops a solid cardiovascular foundation and enhances their aerobic fitness. This is followed by a shorter Build Phase that capitalizes on this foundation through intense, specialized training aimed at enhancing speed, strength, and discipline-specific skills. It is important to note that the different phases focus on training different muscle fibers and processes in the body and one can’t replace the other. If you are a runner who wishes to improve their speed, you won’t be able to train it with easy high volume runs. If you desire staying power and general cardiovascular fitness, running at the maximum effort all the time won’t get you there.

This structure of a typical training cycle with four phases is applicable to various endurance disciplines, such as running, biking, or mountaineering, and caters to athletes of all levels, from beginners to elite competitors. The principles of intensity and volume distribution can even be applied, to some extent, to resistance training.

Training Periods Explained

As said, a well-organized training plan typically comprises four distinct periods:

  1. Base Period: Lasting 8 to 16 weeks, the Base Period focuses on building aerobic endurance and refining technique through low-intensity, high-volume workouts.
  2. Build Period: Spanning 4 to 8 weeks, this phase aims to increase workout intensity while maintaining or slightly reducing volume, incorporating tempo runs, hill training, and interval sessions to improve speed, aerobic capacity, lactate threshold, and race-specific fitness.
  3. Peak Period: Over 2 to 4 weeks, athletes sharpen their fitness by integrating high-intensity workouts, race-pace sessions, and fine-tuning their physical and mental preparedness for competition.
  4. Taper & Rest Period: Lasting 1 to 3 weeks, this phase involves a gradual reduction in training volume and intensity, allowing the body to recover, adapt, and achieve optimal readiness for the target race or event.

Understanding the structure of a training periodization and its various phases is essential for maximizing performance and ensuring effective progress towards your goals. The Taper & Rest Period, which may be surprising in its length, is a crucial component that completes the cycle, lets the body rapidly adapt and sets the stage for future success.

Different periods, their intensity and length within a training cycle

Base Period Training

The Base Period is typically the first phase of your training plan, lasting anywhere from 8 to 16 weeks, depending on your fitness level and training goals. The primary focus during this period is on developing aerobic endurance and overall fitness. Training sessions in the Base Period are characterized by:

  1. Low to moderate intensity: The majority of workouts in the Base Period should be in the lower heart rate zones (zones 1-3), focusing on building aerobic endurance and basic fitness. This intensity allows for the development of capillaries and mitochondria, which are essential for delivering oxygen and nutrients to your muscles. Furthermore the intensity allows the slow twitch muscle fibres responsible for endurance to get trained and improved.
  2. Long, steady workouts: To get improvement out of your slow twitch muscles, you need to exhaust them with large volume of effort. The Base Period lets you do this alongside building up your aerobic base with long, steady workouts. These sessions should be performed at a comfortable pace, allowing for conversation and nasal breathing.
  3. Easy recovery and low fatigue: The intensity and structure of Base Period trainings can be sustained for long durations and can be recovered from quickly. The trainings do not cause deep fatigue. This lets you to pursue greater training volume and larger improvements.

Benefits of the Base Period Training

The Base Period provides several key benefits that will set you up for success later in your training plan:

  1. Enhanced aerobic capacity: By focusing on aerobic endurance, you will improve your body’s ability to efficiently use oxygen and fuel during exercise. This will allow you to perform at a higher intensity for longer periods without fatigue.
  2. Development of slow twitch muscles: Base period training focuses on building slow twitch muscle fibers, which are crucial for endurance and stamina. These fibers rely on aerobic metabolism and are more fatigue-resistant than fast twitch fibers. Training slow twitch muscles during the Base Period allows for a solid aerobic foundation, which can be further built upon in subsequent training phases. High-intensity workouts in the Build and Peak Periods predominantly target fast twitch fibres, making the Base Period essential for comprehensive muscle development.
  3. General development of cardiovascular health: Base Period training strengthens the heart, lungs, and circulatory system, promoting overall cardiovascular fitness and reducing the risk of heart disease and other related health issues.
  4. Injury prevention: By gradually increasing the volume and intensity of your workouts during the Base Period, you give your body the opportunity to adapt to the stress of training, reducing the likelihood of injury or overtraining.
  5. Mental preparation: The Base Period allows you to establish a consistent training routine and develop the mental discipline required for more intense training in the Build Period.

Heart Rate Zones

To establish how hard the training in the Base Period should be, we will use heart rate zones. Heart rate zones are defined as ranges of heart rate levels that correspond to different exercise intensities. These zones are used to help individuals tailor their workouts to achieve specific fitness goals, such as improving endurance, increasing speed, or burning fat. The zones are typically divided into four to five categories, although some systems may use more or fewer zones. The ranges where these zones begin and end are approximate and you will find different sources name them differently. Here is a general breakdown of the heart rate zones:

Training ZoneHeart rate rangeExertionVentilationBenefits
Recovery & Stress Relief< 50%Very lightEffortless conversation, nasal breathingMuscle recovery, stress relief
Zone 1 – Basic Endurance & Fat Burning50% – 60%LightEffortless conversation, nasal breathingBasic endurance, fat burning
Zone 2 – Aerobic Capacity & General Fitness60% – 70%ModerateConversation bit difficult, able to keep nose breathingImproved aerobic capacity, fat burning
Zone 3 – Cardiovascular Fitness & Stamina70% – 80%Moderately hardMinimum conversation, few words, mouth breathing necessaryImproved cardiovascular fitness
Zone 4 – Lactate Threshold & Intense Training80% – 90%HardNo conversation, mouth breathingIncreased lactate threshold

Exercise longer at high intensity without fatigue
Zone 5 – Maximum Performance & Speed Development90% – 100%MaximumNo conversation, mouth breathingImproved speed and power
Overview of heart rate zones, their characteristics and benefits of training within them

Determining your Maximum HR and Zones

Determining the heart rate zone you’re currently exercising in can be done through both technical and intuitive methods. Technical solutions involve using heart rate monitors, fitness trackers, or smartwatches that measure your heart rate during exercise. These devices typically display your current heart rate and sometimes even indicate the corresponding zone. On the other hand, intuitive measurements rely on your body’s signals, such as ventilation and perceived exertion.

For instance, if you can breathe comfortably through your nose and maintain a conversation, you’re likely in a lower heart rate zone (zones 1-2). As the intensity increases and you start breathing through your mouth, conversing becomes difficult, indicating that you’ve moved into a higher heart rate zone (zones 3-4). In the highest zone (zone 5), conversation is nearly impossible, and you’re breathing heavily. By combining both technical and intuitive methods, you can effectively gauge which heart rate zone you’re in during your workouts.

Note that if you rely on technical means, you should find a sports clinic near you and invest into professional measurement of VO2 Max and your heart rate zones. This is important, because relying on the usual statistical guessing of your maximum heart rate (the typical “220 minus your age”) is not reliably applicable to your individual metabolism. It has been found that maximum heart rates vary significantly between individuals. Even within a single elite sports team, such as Olympic rowers in their 20s, maximum heart rates have been reported as varying from 160 to 220. With this in mind, I recommend that regardless of technical tools, you first and foremost listen to your body, observe the breathing, perceived effort and your ability to have a conversation during a training. This will be a tool more reliable to an amateur athlete than any device.

Base Period Training Intensity

Given definition we provided for Base Period training before, we can now specify that such training includes staying mostly in zones 1 and 2. This may seem strange to a beginner athlete, but in fact even the most elite endurance athletes in the world spend 85% of their time training at these low intensities. These are where a lot of basic fitness and endurance will be developed, without incurring too much fatigue cost on the athlete’s body.

Skipping Base Period

Skipping the Base Period and jumping straight into high-intensity training can be counterproductive and may not lead to the desired improvements in endurance and general fitness. The Base Period serves as a critical foundation, gradually preparing the body for the stress and demands of more intense training. By bypassing this phase, you risk overloading your system, which can lead to overtraining, injury, and burnout. Furthermore, high-intensity training alone does not efficiently develop the aerobic capacity, capillary density, and mitochondrial function necessary for endurance sports. These adaptations are best achieved through low to moderate intensity workouts, which are the focus of the Base Period.

Therefore, neglecting the Base Period can result in an imbalanced fitness profile and hinder your long-term progress, ultimately preventing you from reaching your full potential. Even if you manage to avoid injury, training at only high intensity will lead to an actual decrease of your performance due to fatigue. To understand why, let’s look at few explanations of the cycle of fatigue and recovery.

Recovery and Fatigue

Managing fatigue plays an important role in any training plan. It’s important to understand that different training intensities demand varying lengths of recovery time. Generally, the higher the intensity of a workout, the longer the recovery period needed for your body to fully recover and adapt. Here’s a quick breakdown:

  1. Low-intensity training (e.g., Base Period workouts, easy runs): These workouts place less stress on the body and usually require shorter recovery times, often as little as half a day.
  2. Moderate-intensity training (e.g., tempo runs, steady-state sessions): These workouts create more physiological stress and typically require a slightly longer recovery period, between one and two days.
  3. High-intensity training (e.g., interval workouts, hill sprints, races): These sessions are the most demanding on the body and generally require the longest recovery times, which can take multiple days, depending on the individual and the workout’s intensity.

The Dangers of Insufficient Recovery

When recovery periods are consistently too short, fatigue accumulates, and your body doesn’t have enough time to adapt and repair the damage caused by training. This can lead to a downward spiral of overtraining, characterized by symptoms such as:

  1. Persistent fatigue and lack of energy
  2. Decreased performance and stalled progress
  3. Increased risk of injury and illness
  4. Hormonal imbalances and sleep disturbances
  5. Mood changes, irritability, and loss of motivation

The consequences of overtraining can be severe, taking weeks, months, or even longer to fully overcome. This makes it crucial to prioritize recovery and listen to your body’s signals to avoid pushing too hard, too soon.

Cycle of training after insufficient recovery that leads to overtraining and loss of fitness
Cycle of sufficient recovery, supercompensation and good timing followup training that leads to increase in aerobic fitness

Runner’s First Week Training Example

To give you an idea of a structure of a Base Period training for a beginner runner, I’ll share a week’s typical training schedule. It is important to note that it is meant as an example to illustrate the approach, and that concrete runners would have variations coming from their baseline fitness and other kinds of trainings they might want to incorporate in their week (e.g. resistance training).

25 min, Zone 2

Explosive sprint finish at maximum effort
20 min, Zone 1/2

Should feel easy, to recover from intensity yesterday
Rest day25 min, Zone 2

Explosive sprint finish at maximum effort
20 min, Zone 1/2

Should feel easy, to recover from intensity yesterday
40 min, Zone 2

Longest duration of the week, to push endurance adaptations
Rest Day
Example training plan for a beginner runner

Development of Training Volume Throughout Base Period

As I stated earlier, the Base Period focuses on larger volume of manageable training to trigger adaptations in the body. That implies that as the training progresses and one’s fitness improves through the Base Period, the volume of performed training will gradually increase as well. To successfully increase training volume during the Base Period, follow these guidelines:

  1. Start with a manageable volume: Begin your Base Period with a training volume that is comfortable and sustainable, based on your current fitness level and previous training experience.
  2. Increase volume gradually: Aim to increase your weekly training volume by 5-10% each week, allowing your body to adapt to the new workload without overwhelming it. Remember that individual response to volume increase may vary, so adjust the rate of progression based on how your body reacts.
  3. Incorporate step-back weeks: Every 3-4 weeks, reduce your training volume by 10-20% for a “step-back” week, allowing your body to recover and absorb the accumulated workload. This approach helps prevent overtraining and keeps you feeling fresh and motivated.
  4. Prioritize quality over quantity: While increasing volume is essential during the Base Period, it’s crucial not to sacrifice workout quality. Ensure that you maintain proper form and technique, and avoid pushing too hard during easy or recovery sessions.
  5. Listen to your body: Be mindful of how your body responds to the increasing training volume. If you experience persistent fatigue, excessive soreness, or a decline in performance, consider reducing the rate of volume progression or taking additional rest days to allow for adequate recovery.
Evolution of training volume throughout 12 weeks of Base Period training


The Base Period is a crucial phase in any training plan, particularly for those just starting their exercise journey. It focuses on developing a solid aerobic foundation through low to moderate intensity workouts. This allows the body to adapt and build endurance. Skipping this phase and diving straight into high-intensity training can lead to overtraining, injury, and a decrease in performance. It’s essential to prioritize recovery and gradually increase training volume throughout the Base Period, ensuring a well-rounded and sustainable approach to reaching your fitness goals. By understanding and adhering to the principles of Base Period training and fatigue management, you can set yourself up for long-term success and avoid the common pitfalls of self-sabotage in your fitness journey.


Olbrecht, J. (2007). The science of winning planning, periodizing and optimizing swim training. F & G Partners, Partners in Sports. 

House, S., & Johnston, S. (2014). Training for the new alpinism: A manual for the climber as athlete. Patagonia Books. 

Noakes, T. (2003). Lore of running. Human Kinetics. 

Bettin, A. (2022, March 31). Are you recovering adequately between high-intensity workouts? TrainingPeaks. Retrieved April 3, 2023, from https://www.trainingpeaks.com/blog/are-you-recovering-adequately-between-high-intensity-workouts/

Fatigue recovery, and supercompensation – teamunify. (n.d.). Retrieved April 3, 2023, from https://www.teamunify.com/cseksc/__doc__/Shea_FatigueRecoverySupercompensation-2.pdf 

Kolata, G. (2001, April 24). ‘maximum’ heart rate theory is challenged. The New York Times. Retrieved April 3, 2023, from https://www.nytimes.com/2001/04/24/health/maximum-heart-rate-theory-is-challenged.html   

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