Memory decline is often automatically associated with dementia, yet research consistently shows that a wide range of lifestyle, medical and environmental factors can impair memory performance (Baddeley, Eysenck and Anderson, 2020; NHS, 2023). Many causes of memory difficulties are reversible or manageable, particularly when identified early. Evidence from neuroscience, endocrinology and public health demonstrates that stress, sleep deprivation, nutritional deficiencies, thyroid dysfunction, medications, alcohol misuse and transient ischaemic attacks (TIAs) can all disrupt the processes of encoding, storage and retrieval. Understanding these factors is essential in protecting cognitive health across the lifespan.
1.0 Chronic and Acute Stress
Stress is one of the most underestimated contributors to memory difficulties. When under prolonged pressure, the body releases elevated levels of cortisol, the primary stress hormone. Chronic exposure to cortisol has been shown to impair hippocampal functioning — the brain region crucial for memory consolidation (Lupien et al., 2009).
In the UK alone, hundreds of thousands of workers report stress-related illness annually (Health and Safety Executive, 2023). Research demonstrates that individuals with persistently high cortisol levels perform worse on memory tests, particularly tasks involving recall and working memory (McEwen, 2017). Even severe short-term stress can disrupt retrieval processes.
What to Do
Engage in evidence-based stress reduction strategies such as:
- Regular physical activity
- Mindfulness or yoga
- Time in nature
- Relaxation techniques
Exercise, in particular, has been shown to buffer cortisol’s negative effects on the brain (WHO, 2022).
2.0 Sleep Problems
Sleep is fundamental to memory consolidation. During deep sleep stages, the brain transfers information from short-term storage into long-term memory (Walker, 2017).
Adults typically require at least six to eight hours of quality sleep. Both sleep deprivation and fragmented sleep are associated with poorer cognitive performance (NHS, 2023).
Conditions such as sleep apnoea, characterised by repeated breathing interruptions, can significantly impair memory and attention the following day (Healthline, 2022). Repeated oxygen deprivation disrupts neural efficiency.
What to Do
- Establish a consistent sleep routine
- Avoid caffeine and alcohol before bedtime
- Seek medical advice if heavy snoring or daytime fatigue occurs
Untreated sleep disorders are strongly linked to cognitive decline.
3.0 Vitamin B12 Deficiency
Vitamin B12 is essential for red blood cell production and nervous system integrity. Deficiency can lead to anaemia and neurological symptoms, including memory loss (NHS, 2023).
Older adults are particularly at risk due to reduced absorption. Symptoms include:
- Fatigue
- Dizziness
- Tingling in hands and feet
- Confusion
Prolonged deficiency may cause irreversible nerve damage if untreated.
What to Do
Consult a GP if symptoms arise. Treatment typically involves B12 injections or supplements. Dietary sources include:
- Meat
- Fish
- Eggs
- Dairy products
Vegans should consider fortified foods or supplementation.
4.0 Thyroid Disorders
An underactive thyroid (hypothyroidism) can mimic age-related cognitive decline. Low thyroid hormone levels slow metabolism, affecting brain function (British Thyroid Foundation, 2023).
Common symptoms include:
- Fatigue
- Memory problems
- Cold intolerance
- Weight gain
- Constipation
Hypothyroidism is more common in women and older adults.
What to Do
A simple blood test can confirm diagnosis. Treatment involves thyroxine replacement therapy, which typically restores cognitive function.
5.0 Medication Side Effects
Certain medications can impair memory, especially in older adults. Drugs with anticholinergic properties block acetylcholine, a neurotransmitter vital for learning and memory (Campbell et al., 2009).
These medications are often prescribed for:
- Bladder conditions
- Insomnia
- Allergies
- Nausea
Ageing slows metabolism, meaning drugs remain in the system longer and may accumulate.
What to Do
Keep an updated list of all medications, including over-the-counter drugs. Discuss concerns with a GP, who may adjust dosages or alternatives.
6.0 Alcohol Misuse
Excessive alcohol consumption damages brain tissue and interferes with neurotransmitter systems. Chronic heavy drinking is associated with alcohol-related brain damage (ARBD) (NHS, 2023).
Even binge drinking can cause short-term memory blackouts due to disrupted hippocampal function (Harvard Health Publishing, 2021).
What to Do
Follow UK guidelines:
- Men and women should drink no more than 14 units per week
- Spread intake across several days
Avoid binge drinking entirely to protect brain health.
7.0 Mini-Stroke (Transient Ischaemic Attack)
A transient ischaemic attack (TIA) occurs when blood flow to part of the brain is temporarily interrupted. Although symptoms may resolve within minutes or hours, TIAs are serious warning signs (NHS, 2023).
Symptoms include:
- Sudden confusion
- Speech difficulties
- Memory loss
- Loss of balance
- Dizziness
Around one in five individuals who experience a TIA will have a full stroke within three months (Stroke Association, 2023).
What to Do
Treat symptoms as a medical emergency, even if they disappear. Immediate evaluation reduces stroke risk.
8.0 Normal Ageing vs. Pathology
Some degree of memory change is a natural part of ageing. Processing speed may slow, and retrieval may take longer (Salthouse, 2019). However, significant memory impairment that interferes with daily life is not normal.
Distinguishing between benign forgetfulness and pathological decline is essential. For example:
- Forgetting where you placed keys occasionally is common.
- Forgetting what keys are used for is concerning.
Regular cognitive stimulation, physical activity and social engagement protect against accelerated decline (WHO, 2022).
While mild memory changes may occur with age, many causes of memory difficulty are modifiable or reversible. Stress, sleep problems, nutritional deficiencies, thyroid disorders, medications, alcohol misuse and mini-strokes can all affect the delicate processes of encoding, storage and retrieval.
The key message is reassurance: memory loss does not automatically signal dementia. Early recognition and intervention can protect long-term cognitive health. Protecting memory requires proactive care—adequate sleep, balanced nutrition, stress management and medical awareness.
Your memory is a living system. Treat it accordingly.
References
Baddeley, A., Eysenck, M.W. and Anderson, M.C. (2020) Memory. 3rd edn. London: Psychology Press.
British Thyroid Foundation (2023) Hypothyroidism and cognitive symptoms. Available at: https://www.btf-thyroid.org.
Campbell, N.L. et al. (2009) ‘The cognitive impact of anticholinergics’, Journal of Clinical Interventions in Aging, 4, pp. 225–233.
Harvard Health Publishing (2021) How alcohol affects memory. Available at: https://www.health.harvard.edu.
Health and Safety Executive (2023) Work-related stress statistics. Available at: https://www.hse.gov.uk.
Lupien, S.J. et al. (2009) ‘Effects of stress throughout the lifespan on the brain’, Nature Reviews Neuroscience, 10, pp. 434–445.
McEwen, B.S. (2017) ‘Neurobiological and systemic effects of chronic stress’, Neurobiology of Stress, 1(1), pp. 3–12.
NHS (2023) Memory loss and causes. Available at: https://www.nhs.uk.
Salthouse, T.A. (2019) ‘Trajectories of normal cognitive ageing’, Psychological Science in the Public Interest, 20(1), pp. 3–51.
Stroke Association (2023) Transient ischaemic attack (TIA). Available at: https://www.stroke.org.uk.
Walker, M. (2017) Why We Sleep. London: Penguin.
World Health Organization (2022) Risk reduction of cognitive decline and dementia. Geneva: WHO.
