雅思阅读 130: The Runner Who Could Not Stop（停不下来的跑者）

改编从 University of Sydney / PMC / BMJ Open SEM（2025年）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：http://www.sydney.edu.au/charles-perkins-centre/news-and-events/news/2025/10/31/the-hidden-costs-of-excessive-exercise--when-fitness-becomes-a-f.html

Reading Passage

A. Everyone knows that exercise is medicine. Walking, cycling, lifting weights and running are among the most reliably beneficial behaviours a human can adopt: they strengthen the heart, improve insulin sensitivity, lift mood and extend lifespan. Public-health guidelines, from the World Health Organization to national institutes, uniformly urge adults to move more. But a small and growing body of research suggests that, beyond a certain dose, the same medicine can become a poison. The problem is not occasional hard training; athletes have long understood that adaptation requires stress followed by recovery. The problem arises when the stress keeps accumulating without the recovery — when the weekly mileage never falls, when rest days feel guilty rather than restorative, and when a runner continues training through injury, illness or worsening performance. This is the territory of overtraining syndrome and, in its psychological form, exercise addiction. The distinction matters: OTS is a physiological condition brought on by insufficient recovery from training load, while exercise addiction is a behavioural disorder in which the drive to move persists even when training is medically contraindicated. The two frequently overlap, but they do not always appear together. A recreational runner who logs eighty kilometres a week without any compulsion, and who rests when advised, is not an addict; the diagnosis requires a persistent drive to exercise despite evidence that the behaviour is harmful, and distress when exercise is prevented.

B. Overtraining syndrome is most often seen in endurance athletes — runners, rowers, triathletes and cyclists — and it manifests as a persistent drop in performance that no amount of rest immediately reverses. Unlike a few days of heavy legs after a tough race, OTS can take months to resolve. Its causes are thought to be multiple and overlapping: chronic glycogen depletion from repeated high-volume workouts, dysregulated inflammatory cytokine signalling, oxidative stress outstripping the body's antioxidant capacity, and disturbances of the autonomic nervous system that controls heart rate, sleep and stress responses. A 2025 review in a physiology journal highlighted that overtraining also affects the central nervous system itself: studies of mice found elevated proteins in brain-derived extracellular vesicles that are markers of oxidative stress, suggesting that the brain, not just the muscles, fatigues under excessive training. A separate analysis of former Olympic rowers found that they were 6.8 times more likely to develop atrial fibrillation — an irregular heartbeat — than non-athletes, even without conventional risk factors, implying that decades of extreme endurance load carry their own cardiovascular price.

C. The psychological dimension is at least as important as the physiological one. Exercise addiction — a compulsive need to keep training despite injury, family consequences or declining performance — has been associated with high levels of psychological distress in studies of athletes. A 2025 cross-sectional survey published in BMJ Open Sport & Exercise Medicine found that addiction risk correlated strongly with body-image distress (correlation 0.45), anxiety (0.42) and stress (0.40), and negatively with self-esteem (−0.36). Hierarchical regression showed that psychological factors explained more than half of the variance in addiction risk. The disorder often coexists with eating disorders: restricting food and over-exercising feed the same body-image anxiety, and stopping either behaviour is experienced as a loss of control. Unlike other addictions, exercise is socially endorsed — praise for a "hard-core" training ethic makes the behaviour harder to recognise as pathological, both by the athlete and by coaches who benefit from the athlete's output.

D. Even recreational exercisers, not just elites, may cross a dose threshold at which benefits reverse. A 2025 animal study put mice through twelve weeks of treadmill programmes calibrated to human energy expenditure. Moderate weekly exercise produced the expected cognitive gains — better spatial memory, faster learning. But mice pushed into the excessive range, above 450 MET-minutes per week of vigorous activity, performed worse on both spatial and non-spatial memory tasks than sedentary controls. The finding echoed earlier epidemiological observations that the very highest-mileage runners face elevated risks of atrial fibrillation, coronary calcification and, paradoxically, reduced longevity. The relationship between exercise dose and health, in other words, is not a straight upward line; it is an inverted U. Most people are far below the peak, but the small minority at the far right of the distribution can do themselves harm by doing more of a good thing. Public-health messaging has been slow to acknowledge this curve, partly because the risk of discouraging sedentary people from ever starting to exercise feels larger than the risk of discouraging a tiny elite minority from overdoing it.

E. Recovery from OTS is neither quick nor simple. Case studies published in 2025 describe endurance athletes who, after months of performance decline and mood disturbance, underwent structured interventions: increased caloric intake, a complete pause from structured training, improved sleep, and psychological support. After twelve weeks, markers such as morning cortisol, growth hormone and resting testosterone began to normalise, and athletes gradually returned to sport through a phased programme supervised by sports medicine specialists. The central lesson is that OTS is not cured by more training, and that prevention depends on monitoring resting heart rate, mood, sleep and performance as carefully as mileage. For coaches and clinicians, the challenge is distinguishing the productive fatigue of a well-designed training block from the chronic exhaustion of an athlete whose body has stopped adapting. For the wider culture, the harder lesson is that the same social praise which encourages fitness can, in a minority, become the trigger for a pattern that eventually destroys the very performance it was meant to build. Coaches, too, are only beginning to be trained to recognise the early signs — persistent fatigue, declining mood, reduced sleep — rather than rewarding athletes for pushing through them. Education for young athletes about the difference between productive hard training and chronic overload is increasingly part of national sports-medicine curricula.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. What overtraining syndrome is — and its physical mechanisms ii. The psychology of exercise addiction iii. Even recreational exercisers can cross the dose threshold iv. Recovery and prevention v. How to train for a marathon vi. The history of endurance running vii. Why sleep is important for weight loss

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. According to the rower study, former Olympic rowers were how much more likely to develop atrial fibrillation? A. 2.8 times. B. 4.5 times. C. 6.8 times. D. 10 times.

6. What did the BMJ Open study find about exercise addiction risk? A. It was unrelated to psychological factors. B. It correlated strongly with body-image distress, anxiety and stress. C. It affected only professional athletes. D. It was highest among low-mileage runners.

7. What did the mice study find about excessive exercise? A. It improved spatial memory. B. It caused worse memory performance than sedentary controls. C. It had no cognitive effect. D. It reduced anxiety.

8. What shape does the exercise-dose vs health relationship follow? A. A straight upward line. B. An inverted U. C. A flat line. D. A downward slope.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. Overtraining syndrome is most often seen in sprinters and weightlifters.
10. Central nervous system fatigue markers were found in overtrained mice.
11. Psychological factors accounted for about half of the variance in exercise addiction risk.
12. Most regular runners exceed the excessive-exercise threshold.
13. Recovery from OTS usually requires increasing training volume.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Overtraining syndrome involves multiple overlapping mechanisms including glycogen depletion and (14) __________ stress. Recovery typically requires a pause from training, improved (15) __________ and psychological support.

答案与解析

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