She stayed at home and remembers thinking "I'm going to die".
Almost a year later, after surgery and chemotherapy (an experience she would not like to repeat), she is feeling great, getting on with life and not dwelling on the disease.
She still has tingling in her fingers and toes and feels the cold more than she used to - side-effects from the chemotherapy - but she feels lucky.
A fit woman with a healthy diet, Mrs Bartlett had visited her GP, Dr Ruth Barnett, last June about a stye in her eye, and during the consultation was asked if she had any other concerns.
She mentioned that she was getting intermittent "cruel" stomach pains which she believed might be giardia or caused by her blood-pressure medication .
Her doctor said this was not an expected side-effect and referred her for a private appointment with endoscopist and general surgeon Tom Elliott in July last year.
He was able to feel a lump in her lower abdomen.
A colonoscopy on August 4 confirmed that she had a cancerous colon tumour, and on August 13 she underwent surgery at Mercy Hospital to have it removed.
The cancer was found to have spread to two lymph nodes near the colon.
Her surgery was followed by eight cycles of chemotherapy over six months through Dunedin Hospital.
She described the staff in the oncology day unit as "wonderful people who were so empathetic - they just knew how you felt and how you were going to feel".
Each cycle involved the administration of intravenous medication over two to three hours every three weeks, followed by two weeks of taking 12 tablets a day, followed by a time without medication before the cycle started again.
She was lucky enough not to lose her hair during the chemotherapy.
Mrs Bartlett, who works in education, said her employers were extremely supportive and allowed her to work when she could.
She praised all those involved in her care, mentioning the conscientiousness of her GP and the reassuring but clear way Mr Elliott explained diagnosis, treatment and prognosis.
She acknowledged the part having private medical insurance played in the speed of her treatment.
"Not everybody is as lucky as me."
Mrs Bartlett said if she had been referred in the public system she expected she would have had to wait much longer for a colonoscopy and she was hopeful the new Beat Bowel Cancer Aotearoa group would be able to agitate for shorter waiting times and a more equitable system.
"Immediacy of diagnosis and operation could save a whole lot of lives, but some people have to wait for colono-scopy for six to nine months. If I had to wait that long, I'd possibly be in a much more serious situation now."
Making people more aware of the possible symptoms of the illness was also important.
Having people around her who "didn't make nuisances of themselves" but just kept a check on her from time to time and listened to her, had helped immensely during her treatment.
While her husband, Paul, was an "absolute rock", and so were her grown-up children Kate and Jeff and their families, she was conscious of not wanting to burden them.
"Being able to tell someone else 'I feel lousy today' was helpful."
She felt the new organisation could be valuable in providing extra support to those people who might not have close friends or family.
"I can't imagine what it would have been like in a little flat by myself with no-one to talk to."
Today, Mrs Bartlett is making the most of life. She is aware of the need to keep fit, but does more walking and less running than she used to, watches her diet without "going overboard" and feels secure about ongoing monitoring of her health, which includes a private colonoscopy next month.