Training & Fitness - Running & endurance
Tempo and threshold training
Last updated 1 October 2026. How we write this .
Tempo and threshold training develop sustained endurance through controlled, demanding efforts. Their value depends on accurate pacing, recovery and a foundation of easy training.
Start here Tempo and threshold training develop sustained endurance through controlled, demanding efforts. Their value depends on accurate pacing, recovery and a foundation of easy training.
By the end, you will understand What the terms actually mean Why a small pace increase changes the effort What training can change, and what evidence shows Where this information comes from Claim-cited evidence. Central research claims on this lesson are linked to specific studies or official guidance.
This lesson links the specific studies and guidance used for its central claims.
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Tempo and threshold training use controlled, sustained efforts to develop the ability to maintain a demanding pace. Threshold work sits near the upper boundary of relatively stable endurance exercise, rather than becoming an all-out time trial. Tempo is a less precise coaching term that may mean threshold work or a somewhat easier, prolonged effort.
What the terms actually mean
A training threshold is a boundary between patterns of physiological response, not a switch that suddenly changes which energy system works. Researchers identify several thresholds using blood lactate, breathing measurements or performance tests. These methods describe related features of endurance capacity, but their results are not interchangeable.
The first threshold marks a departure from easier exercise, with changes in lactate or breathing becoming detectable. Coaches discussing a threshold session usually mean a higher, second threshold. Around this higher boundary, maintaining the same speed becomes substantially more demanding, and small increases in pace can shorten the time someone can continue.
Tempo has no universally agreed definition. One coach may use it for sustained running below the second threshold; another may use it as a synonym for threshold running. A useful session description therefore explains its intended effort and purpose, rather than relying on the word tempo alone.
Why a small pace increase changes the effort
Working muscles continually regenerate ATP, the immediate energy source for contraction. As running speed or cycling power rises, ATP demand increases. Oxygen-supported metabolism supplies much of this energy, while the breakdown of carbohydrate also produces lactate that other tissues can use as fuel.
Lactate is not simply a waste product, and its presence does not mean that muscles have run out of oxygen. Blood lactate reflects the balance between its appearance and removal. A stable reading can coexist with substantial production because lactate is also being transported and used.
Near the upper boundary of sustainable exercise, the body has less room to accommodate an increase in demand. Above it, oxygen consumption and other physiological disturbances may continue rising despite an unchanged pace. Fatigue develops through interacting processes, including changes within muscle cells and the increasing effort needed to maintain force, rather than one substance accumulating in isolation.
This explains why a slightly overambitious start can change the whole session. A pace that feels manageable while fresh may become progressively harder instead of settling. Threshold training aims to create a substantial endurance stimulus while retaining control over that progression.
What training can change, and what evidence shows
Repeated endurance training can increase the capacity of muscles to use oxygen, support adaptations in mitochondria and capillaries, and change lactate transport and use. These adaptations can contribute to a faster pace at a comparable physiological demand. They are not exclusive to threshold sessions: easier endurance work and harder intervals can also contribute.
Small controlled trials in runners, cyclists and other endurance athletes show that programmes containing threshold work can improve performance or physiological measures. However, many studies are short and involve trained participants. Their findings do not establish an ideal session frequency for a beginner, an older adult or someone returning after illness.
Randomised comparisons of training distributions have sometimes favoured programmes combining substantial easy training with a smaller amount of harder work over programmes heavily concentrated around threshold. Results depend on the participants, the outcome measured and how training load is matched. Evidence for one universally superior distribution remains mixed.
Observations of successful athletes show how threshold sessions fit into real training, but cannot prove which component caused their success. Athletes differ in training history, recovery opportunities and selection into elite sport. The reasonable conclusion is that threshold work is a useful option, not a requirement for every endurance goal or a shortcut around consistent training.
A threshold is an estimate made under particular conditions. Neither a laboratory result nor a watch-generated number creates an exact boundary that remains fixed through heat, fatigue, hills and changes in fitness.
Recognising controlled effort
Threshold effort is often described as comfortably hard, but that phrase can mislead. Breathing is clearly elevated and conversation becomes limited; the effort requires attention without feeling like a finishing sprint. Speech and perceived effort provide clues, not a precise measurement of the second threshold.
Heart rate adds context but responds with a delay and can rise during a steady effort, particularly in heat. Pace is affected by hills and wind, while wrist sensors can produce errors. Chasing a heart-rate target early in a session can therefore push someone faster than intended before the reading catches up.
Laboratory testing can use blood lactate or respiratory gases to estimate relevant boundaries. The testing method, stage length and interpretation affect the result. Field tests and wearable estimates are more accessible, but they infer physiology from performance or sensor data; a precise-looking number does not necessarily have precise accuracy.
A useful judgement combines pace or power, breathing, perceived effort and how the effort changes over time. Rapidly escalating strain, deteriorating movement or an inability to maintain the intended effort suggest that the session is no longer serving its original purpose. Finishing exhausted is not evidence that threshold intensity was identified correctly.
Common formats and their trade-offs
A continuous controlled effort: useful for practising an even effort without a reset, but vulnerable to starting too fast. Longer repetitions separated by short easy recoveries: allow demanding work to be accumulated with opportunities to reassess control. Race-specific blocks later in a plan: connect sustained effort with an event's demands, although race pace is not automatically threshold pace. Breaking an effort into repetitions does not automatically turn it into a harder interval session. Recoveries can help preserve the intended intensity and movement quality. However, accelerating each repetition because a break is coming changes the demand; the session label cannot compensate for excessive speed.
Race-specific work needs particular care in interpretation. The same event can take very different amounts of time for different runners, so its pace does not represent the same physiological intensity for everyone. Event preparation belongs within the relevant distance lessons; here, the central question is whether the effort matches the intended endurance stimulus.
Who it suits and where it fits
Threshold work is most relevant to people who already tolerate regular endurance activity and want to improve sustained performance. A newer runner with that foundation may find one purposeful session in a week enough. This is a conservative coaching judgement, not a universal requirement or a result established for every population.
Adding intensity before consistent easy running usually reverses the useful order of development. Someone still establishing a running habit can improve without threshold sessions. The beginner running and easy cardio lessons cover that foundation; faster work has value only when its recovery cost fits the wider pattern of activity.
Progress need not mean increasing both speed and demanding work together. Better control, a steadier effort and normal recovery before subsequent activity are meaningful improvements. Persistent fatigue, worsening pain or repeated deterioration in ordinary sessions suggest that the overall demand exceeds current capacity.
People with relevant heart or lung conditions, unexplained exercise symptoms, pregnancy-related concerns or an ongoing injury need individual guidance before adopting demanding sessions. Fitness in one activity also does not guarantee readiness in another: a cyclist may have strong aerobic capacity without the tissue tolerance required for hard running.
Safety and judging claims
Stop exercise for chest pain, fainting, severe or unusual breathlessness, new neurological symptoms, or significant or worsening pain. Call 999 for persistent chest pain, severe difficulty breathing, collapse with incomplete recovery, or sudden facial weakness, arm weakness or speech difficulty. Contact a GP for recurring exercise symptoms or persistent pain, and NHS 111 for urgent concerns that are not an emergency. Severe muscle pain, swelling or weakness out of proportion to the session, or dark brown or cola-coloured urine, can signal rhabdomyolysis: contact NHS 111 or go to A&E the same day, or call 999 if very unwell.
Judge claims by asking what threshold means, how it was measured and what outcome improved. Faster running at a laboratory marker is useful evidence, but is not identical to better race performance. A before-and-after improvement without a comparison group cannot separate the session's effects from other training changes.
Be cautious when a claim presents threshold as a single magical pace, attributes fatigue entirely to lactate, or copies an elite athlete's workload without context. A credible explanation acknowledges measurement uncertainty, describes the participants and comparison programme, and accounts for recovery. The session earns its place through repeatable training and useful progress, not through how punishing it feels.
This lesson is general education, not an individual training, nutrition or medical prescription. Adapt activity to your experience and health, and seek qualified advice for symptoms, injury, pregnancy or a medical condition.
Related in this classroom The studies behind this page American College of Sports Medicine position stand: quantity and quality of exercise for developing cardiorespiratory fitness - Medicine & Science in Sports & Exercise, 2011Sources for this classroom
Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.